THE  ANIMAL   PARASITES   OF   MAN 


THE 


ANIMAL  PARASITES  OF 

MAN 

A  HANDBOOK  FOR  STUDENTS  AND  MEDICAL  MEN 


BY 

DR.   MAX    BRAUN 

Professor  of  Zoology  and  Comparative  Anatomy,  and  Director  of  the  Zoological  Museum 
of  the  University  of  Konigsberg,  Prussia 

THIRD    ENLARGED    AND     IMPROVED    EDITION 
With  294  illustrations  in  the  text 

TRANSLATED    FROM   THE   GERMAN    BY   PAULINE    FALCKE 

BROUGHT    UP    TO    DATE    BY 

LOUIS    W.    SAMBON,    M.D.   (NAPLES) 

Lecturer  at  the  London  School  of  Tropical  Medicine  ;   Honorary  Member  of  the  Manila  Medical 
Society  ;  Member  of  the  Soci'etb  de  Medicine  Tropicale,  Paris ;  The  Royal  Medical  and 

Chirurgical  Society ',    <5rV. 

AND 

FRED.    V.   THEOBALD,    M.A. 

Vice- Principal  and  Economic  Zoologist  to  the  South  Eastern  Agricultural  College  ;    President  of 
the  Association  of  Economic  Biologists,  &c. 


NEW      YORK 

WILLIAM    WOOD    AND    COMPANY 

MDCCCCVIII 


PUBLIC  HEALTH  LIB. 


U*  - 


I1W 

PUBLIC 
HEALTH 
LIBRARY 


PREFACE    TO    THE     ENGLISH    EDITION. 


BRAUN'S  work  on  Human  Parasites  is  so  well  known  and  has 
been  so  much  appreciated  that  it  has  already  reached  a  third 
German  edition.  Thanks  to  the  present  publishers  an  English 
translation  appears  which  is  sure  to  be  welcomed  by  the  Anglo- 
Saxon  race. 

The  great  importance  of  parasitology  is  becoming  more  marked 
every  day.  It  is  especially  in  warm  climates  that  this  subject  is 
of  such  interest  medically  ;  but,  nevertheless,  the  practitioner  in 
temperate  and  cold  regions  is  constantly  brought  face  to  face  with 
some  parasitic  infestation. 

The  rapid  strides  made  in  parasitology  make  it  necessary  that 
such  works  as  this  should  be  constantly  revised.  In  this  edition 
a  considerable  amount  of  fresh  matter  has  been  incorporated, 
bringing  it  up  to  date.  The  original  text  has  been  followed  as 
closely  as  possible  ;  additional  matter  is  enclosed  in  brackets. 

The  revision  of  the  Protozoa,  Cestodes  and  Nematodes  has  been 
undertaken  by  Dr.  Sambon  ;  the  Trematodes,  Arthropoda,  &c.,  by 
myself.  A  large  amount  of  fresh  matter  has  been  added  to  the 
Arthropoda  especially  dealing  with  Mosquitoes,  Tsetse  Flies,  Ticks, 
and  other  disease-carriers. 

The  translation  has  been  made  with  much  patience  and  skill 
by  Miss  Falcke,  to  whom  the  editors  are  much  indebted  for  the 
trouble  and  time  she  spent  over  the  work. 

FRED.  V.   THEOBALD. 

Wye  Court,  Wye, 
November,   1905. 


M638661 


CONTENTS. 

PAGE 

ON    PARASITES    IN    GENERAL        ...  ...  i 

Occasional  and  Permanent  Parasitism                 ...  ...  ...              ...              ...  i 

Epizoa,  Entbzoa,  Helminthes               ...  ...  ...             ...  2 

Hermaphroditism  ...              ...              ...              ...  ...  ...             ...  4 

Transmigration       ...             ...              ...              ...  ...  ...             ...  6 

Parasites,  Messmates,  Mutualists        ...             ...  ..  ...             ...  6 

Incidental  and  Pseudo-parasites          . .              ...  ...  . .             ...             ...  6 

The  Influence  of  Parasites  on  the  Host             ...  ...  ...             ...             ...  8 

Origin  of  Parasites...             ...               ..             ...  ..  ...             ...             ...  10 

Derivation  of  Parasites          ...             ...             ...  ...  ...             ...             ...  20 

Change  of  Host      ...             ...                              ...  ...  ...             ...             ...  21 

Literature                 ...             ...             ...              ...  ..  ...             ...             ...  23 

THE   ANIMAL   PARASITES   OF    MAN  ...  25 

A.  Protozoa  (Primitive  Creatures)   ...             ...  ...  ...             ...  25 

General  Characteristics  of  the  Protozoa     ...  ...              ..,.             ...  25 

Classification  of  the  Protozoa       ...             ...  ...  ...             ...             ...  27 

Class  I.  RHIZOPODA        ...             ...             ...  ...  ...                           ...  29 

Order  i.  Amcebina    ...             ...             ...  ...  ...             ...             ...  29 

Gen.  i.  Amoeba,  Ehrbg.   ...             ...  ...  ...              ...  29 

Sp.  i.  Amoeba  coli,  Loesch       ...  ...  ...             ...             ...  30 

2.  Amoeba gingivalis,  Gros.  ...  ...              ...              ...  37 

3.  Amoeba  buccalis,  Sternberg  ...  ...                             ...  37 

4.  Amoeba  dentalis,  Grassi  ...  ...              ...             ...  37 

5.  A mceba pulmonalis,  Artault  ...  ..                             ...  37 

6.  A  mceba  urogenitalis,  Baelz  ...  ...              ...              ...  37 

7.  Amoeba  kartulist,  Dofl.  ...  ...              ...              ...  38 

8.  Amoeba  miurai,  Ijami  ...  ..  ...              ...             ...  39 

9.  Leydenia gemmipara,  Schaud.  ...  ...                             ...  40 

Class  II.  FLAGELLATA  (Mastigophora)        ...  ...  ..  41 

,  A.  Polymastigina       ...             ...             ...  ...  ...  43 

Gen.  i.   Trichomonas^  Donne*          ...  ...  ...  43 

Sp.  i.    Trichomonas  vaginalis,  Donne    ...  ...  43 

2.  Trichomonas  intestinalis,  R.  Lkt.  ...  44 

3.  Trichomonas  pulmonalis  ...  ...  47 

Gen.  2.   Lamblia,  R.  Blanch.           ...  ...  ...               ..             ...  48 

Sp.  i.  Lamblia  intestinalis,  Lambl.  ...  ...  48 

B.    Protomonadina,  Blochm.    ...              ...  ...  ...  51 

Sp.  i.    Cercomonas  hominis,  Dav.  ...  51 

2.  Monas  pyophila,  R.  Blanch.  ...  ...  54 

3.  Cercomonades  in  the  urine  ..."  ...             ...  54 

4.  Trypanosoma,  Gruby    ...  ...  ...                           ...  56 

Trypanosoma      ...             ...             ...  ...  ...                             ..  57 

Class  III.  SPOROZOA        ...            ...            ...  ...  63 

Order  I.  Grcgarinida               ...              ...            ....  .......          ...  ...  63 

Order  2.   Coccidiida  ...  ...  ...             ...  68 


viii.  CONTENTS 

THE  ANIMAL  PARASITES  OF  MAN — contd. 

Protozoa— conld.  I'AGE 

History                ...             ...             ...  ...  ...  ...  68 

Occurrence  of  the  Coccidiida           ...  ...  ...  ...  72 

Development  (Schizogony,  &c.)      ...  ...  ...  74 

Classification  of  the  Coccidia            ...  ...  ...  ..  •••  77 

The  Coccidia  observed  in  Man        ...  ...  ...  ...  ...  77 

Gen.  Coccidium,  R.  Lkt.  ...             ...  ...  ...  77 

1 .  Coccidium  cuniculi  (Riv.)...  ...  ...  . . .  ...  77 

2.  Cocciditim  hominis  (Kiv.)    ...  ...  ...  ...  •••  80 

3.  Coccidium  bigeminum,  Stiles  ...  ...  ...  81 

Doubtful  Species                ...             ...  ...  ...  ...  ..  82 

1 .  Eimeria  hominis  ...              ...  ...  ...  ...  ...  82 

2.  Coccidioides  immitis             ...  ...  ...  ...  ...  3 

3.  Coccidia  of  Dura  Mater  and  Excretory  Organs  ...  ...  84 

4.  Psorosperm  Cysts ...             ...  ...  ...  ...  ...  84 

5.  Severi's  "  Monocystide  Gregarines "...  ...  ..  ...  84 

Order  3.   Hcemosporidia             ...              ...  ...  ...  ...  ...  84 

History                 ...             ...             ...  ...  ...  ...  ...  84 

The  Hsemosporidia  of  Man              ...  ..  ...  ...  ...  90 

1.  Plasmodium  malaria  (Laveran)  ...  ...  •...  ...  92 

2.  Plasmodium  vivax  (Grassi  and  Fel.)  ...  ...  ...  93 

3.  Plasmodium,  sp.    ...             ...  ...  ...  ...  ...  94 

4.  Doubtful  Species  ...             ...  ...  ...  ...  ...  95 

5.  The  Sporogony  of  the  Malaria  Plasmodia        ...  ...  ...  95 

Prophylaxis  of  Malaria      ...             ...  ...  ...  ...  101 

Haematozoa  in  Beri-beri    ...             ...  ...  ...  ...  ...  102 

Haamamcebae  in  Leucaemia               ...  ...  ...  ...  ...  103 

The  Haamosporidia  in  Birds,  Reptiles,  Amphibia  and  Fishes     ...  ...  103 

Order  4.  Myxosporidia,  Blitschli            ...  ...  ...  ...  1 06 

History                ...             ...             ...  ...  ...  ...  ...  1 06 

Structure  and  Development  ...  ...  ...  ...  ...  108 

Order  5.   Microsporidia,  Balbiani            ...  ...  ...  ...  ...  no 

Order  6.  Sarcosporidia,  Balbiani             ...  ...  ...  ...  .  112 

History                ...             ...             ...  ...  ...  ...  ...  112 

Structure  and  Development             ...  ...  ...  ...  ...  113 

The  Sarcosporidia  observed  in  Man  ...  ...  ...  ...  116 

Appendix  to  the  Sporozoa        ...             ...  ...  ...  ...  ...  118 

Class  IV.  INFUSORIA  ...  ...  ...  ...  ..  ...  ...  118 

General  Observations                ...             ...  '...  ...  ...  ...  118 

Gen.  i.  Balantidium,  Clap,  et  Lachm.  ...  ...  ...  ...  120 

1.  Balantidium  coh  (Malmst.)  ...  ...  ...  ...  121 

2.  Balantidium  minutum,  Schaud.      ...  ...  ...  ...  125 

Gen.  2.  Nyctotherus,  Leidy             ...  ...  ...  ...  ...  126 

Nyctotherus  faba,  Schaud. .-..  ...  ...  ...  ...  126 

Appendix  to  the  Infusoria                 ...  ...  ...  ...  ...  127 

B.  Platyhelminthes  (Flat- worms)    ...             ...  ...  ...  ...  ...  127 

Classification  of  Platyhelminthes      .'..             ...  ...  ...  ...  ...  128 

Class  I.   Trematoda,  Rud.                 ...             ...  ...  ...  ...  ...  129 

Structure  and  Development      ...             ...  ...  ...  ...  ...  139 

Biology        ..',  ...  ...  I45 

Classification  of  the  Trematodes              ...  ...  ...  ...  ...  147 

The  Trematodes  observed  in  Man           ...  ...  ...  ...  ...  149 

Fam.  i.  Paramphistomidce  (Fischoed)  ...  ...  ...  ...  149 

Gastrodiscus  hominis ...             ...  ...  ...  ...  ...  1 49 

Fam.  2.   Fasciolida,  Raill.               ...  ...  ...  ...  ...  149 


CONTENTS  ix. 

THE  ANIMAL  PARASITES  OF  MAN— contd. 

Platyhelminthes — contd.  PAGE 

Gen.  i.  Pasciola,  L....              ...             ...  ...  ...  ...  149 

Sp.  I.   Fasciola  hepatica    ...              ...  ...  ...  ...  150 

Distomum  oculi  humani,  Amm.      ...  ...  ...  156 

M<mo$tomum  lent  is,  v.  Nordm.        ...  ...  156 

2.   Fasciola  hepatica,  var.  augusta  ...  ...  ...  156 

Gen.  2.  Fasciolopsis,  Looss      ...              ...  ...  ...  ...  158 

Sp.  Fasciolopsis  buski        ...              ...  ...  ...  ...  159 

Disloniuni  rathouisi  ...              ...  ...  ...  ...  159 

Gen.  3.   Paragonimns,  Braun  ...              ...  ...  ...  ...  160 

Sp.  Paragoniinus  ^vestermani          ...  ...  ...  ...  1 60 

Gen.  4.   Opisthorchis^  R.  Blanch.            ...  ...  ...  ...  163 

Sp.  i.   Opisthorchis  felineus,  Riv.    ...  ...  ...  163 

Metorchis  truncatus  (Rud. )  ...  ...  ...  166 

2.  Opisthorchis  sinensis  (Cobb.)  ...  ...  ...  168 

3.  Opisthorchis  noverca,  Braun ...  ...  ...  ...  1 70 

Gen.  6.     Cotylogonimus,  Llihe                 ...  ...  ...  ...  171 

Sp.  Cotylogonimus  heterophyes         ...  ...  ...  ...  172 

Gen.  7.  Dicroc(Kliumt  Dag.     ...             ...  ...  ...  ...  173 

Sp.  Dicroccclium  lanceatum.  Stiles  and  Has?.  ...  ...  174 

Fam.  3.  Schisiosomid(Z)  Looss         ...             ...  ...  ...  ...  176 

Gen.  Schistosotnum,  Weinl.     ...             ...  ...  ...  ...  176 

Sp.  Schistosotnnin  hceniatobinin        ...  ...  ...  ...  176 

Schistosomum  japonicuni           ...  ...  ...  ...  181 

Class  II.   Cestodes,  Rud.  (Tape-worms)          ...  ...  186 

Characteristics  and  External  Conditions                ...  ...  ...  ...  186 

Anatomy  of  the  Cestodes          ...             ...             ...  ...  ...  ...  190 

Development  of  the  Tape- worms             ...             ...  ...  ...  ...  200 

Biology        ...             ...             ...             ...             ...  ...  ...  ...  209 

Abnormalities  and  Malformations           ...             ...  ...  ...  ...  211 

Classification  of  the  Cestodes   ...             ...             ...  ...  ...  ...  212 

The  Cestodes  of  Man               ...             ...             ...  •••,  •••  •••  2I3 

A.  Bothriocephaloidea       ...              ...              ...  ...  ...  ...  213 

Gen.  i.  Dibothriocephalus       ...             ...  ...  ...  ...  213 

Sp.  I.    Dibothriocephahis  lot  us         ...  ...  ...  ...  214 

2.   Dibothriocephahis  cordatus  ....  ...  ...  ...  220 

Gen.  2.  DiplogonoporuS)  Lonnbrg.         ...  ...  ...  ...  221 

Sp.  Diplogonoporus grandis              ...  ...  ...  ...  221 

Bothriocephalus  mansoni,  Cobb.  ...  ...  ...  222 

B.  Tceniidce        ...             ...             ...             ...  ...  ...  ...  223 

Gen.  3.   Dipylijium,  R.  Leuck.             ...  ...  ...  ...  223 

Sp.  Dipy Helium  caninnni  (L. )  ...  ...  ...  ...  223 

Gen.  4.   Hymenolepis,  Weinland             ...  ...  ...  ...  225 

Sp.  I.  Hymenolepis  nana  (v.  Lieb. )  ...  ...  ...  226 

2.  fiynienolepis  ih'mitiula,  Rud.  ...  ..  ...  229 

3.  Hymenolepis  lanceolala,  Bloch.  ...  ...  230 

Gen.  5.   Davainea,  R.  Blanch.                ...  ...  ...  ...  231 

Sp.  I.   Davainea  Madagascar iensis...  ...  ...  ...  232 

2.   Davainea  (?)  asiatica             ...  ...  ...  ...  233 

Gen.  6.    Tcenia,  L.     ...             ...             ...  ...  ...  ...  233 

Sp.  I.    7lenia  soliutn,  L. ,  p.  }\        ...  ...  ...  ...  234 

Cyslicercus  acanthotrias       ...  ...  ...  ...  240 

2.  Tcenia  marginaia,  Batsch.  ...  ...  ...  ...  242 

3.  Tcenia  serrata,  Goeze           ...  ...  ...  ...  242 

4.  Tcenia  crassicollis,  Rud.       ...  ...  ...  243 


x.  CONTENTS 

THE  ANIMAL  PARASITES  OF  MAN—  -contd. 

Platyheltninthes— could.  PAGE 

5.  Tcenia  saginata,  Goeze  ...  243 

6.  Tcenia  afrtcana,  v.  Linstow...  ...  •••  24^ 

7.  Ttf-wm  confusa,  Ward  ...  . .  •  •  •  24& 

8.  Tcznia  echinococcus,  v.  S.ieb....  ...  •••  249 

Structure  and  Development  of  Echinococcus  ...  ...  252 

Echinococcus  multilocularis  ...  ...  •••  257 

-  Tcenia  hominis,  v.  Lstw.  ...  ...  ..,  ...  261 

C.  Nematodes  (Thread- worms)         ...             ...  ...  261 

(a)  Anatomy  of  the  Nematodes  ...             ...  ...  ...  •••  2^2 

(6)  Development  of  the  Nematodes           ...  ...  ...  ...  271 

(c)  Classification  of  the  Nematodes           ...  ...  ...  •••  274 

The  Nematodes  observed  in  Man               ...  ...  ...  •••  275 

(a)  Fam.  Anguilhilida     ...             ...             ...  ...  ...  275 

Gen.  i.   Rhabditis,  Dujardin  ...             ...  ...  ...  ...  ...  275 

Sp.  i.   Rhabditis  pellio  (Schneider)..  ...  ...  '    ...  ...  275 

2.  Rhabditis  niellyi    ...              ...  ...  ...  -   ...  ...  276 

Gen.  2.  Anguillulina,  Gervais  and  Beneden  ...  ...  ...  276 

Sp.  Anguillulina  putrefaciens ,  Kiihn  ...  ...  .<.  ...  276 

(6)  Fam.  Angiostomidce     ...             ...             ...  ...  ..-:•«>-"""  •••  •••  277 

Gen.  3.   Strongy hides,  Grassi ...             ...  ...  '.••>.:  -.  V.t  •••  277 

(c)  Fam.  Gnathostomidce  ...             ...             ...  ...  ...  •».  ••  2$i 

Gen.  4.   Gnathostoma^  Owen  ...             ...  ...  ...  ...»  •••  281 

Gnathosloma  siamense,  Lev.             ...  ...  ...  ...  ...  28 1 

(d)  Fam.  Filariidce           ...             ...             ...  ...  ...  ...  ...  282 

Gen.  5.  Filaria,  O.  Fr.  Miiller              ...  ...  ...  ...  ...  282 

Sp.  I.   FiJaria  medinensis           :     •••,  ,  •••  ...  ...  ...  282 

2.  Filaria  immitis,  Leidy         ...  ...  ...  ...  ...  285 

3.  Filaria  bancrofti,  Cobb.      ...  ...  ...  ...  ...  288 

4.  Filaria  diurna,  P.  Manson...  ...  ..  ...  ...  292 

5.  Filaria perstans,  P.  Manson  ..  ...  ...  ...  293 

6.  Filaria  demarquayi,  Manson          .   ''•••••$>  ••  •  •  •••  2Q6 

7.  Filaria  ozzardi,  Manson      ...  ...  ...  ...  ...  297 

8.  Filaria  magalhcesi,  R.  Blanch.  ...  ...  ...  ...  299 

9.  f Maria  faa,  Guy ot                ...  ...  ...  ...  ...  300 

10.  Filaria  oculi  htimani            ...  ...  ...  ..  ...  302 

11.  Filaria  conjunctive,  Addario  ...  ...  ...  ...  303 

12.  Filaria  restiformis,  Leidy    ...  ..:;.  .,„  -  ...  304 

13.  Filaria  hominis  oris,  Leidy  ...  .,•••:  •••  ...  305 

14.  Filaria  labialis,  Pane           ...  ...  ...  rj.  ...  305 

15.  Filaria  equina  (Abildg.)      ...  ...  ...  ...  ...  305 

16.  Filaria  romanorum-orientalis  ...  ...  ...  ...  307 

17.  Filaria  -volvulus,  R.  Leuck.  ...  ...  ...  ...  307 

18.  Filaria  kilimara;,  Kolb        ...  ...  ...  ...  ...  309 

19.  Filaria,  sp.?           ...              ...  ...  ...  ...  ...  309 

(<?)  Fam.  Trichotrachelidtf                ...              ...  ...  ...  ...  ...  309 

Gen.  6.   Trichocephalus,  Goeze               ...  ...  ...  ...  ...  309 

Sp.  Trichocephalus  trichiurus  (L.)  ...  ...  ...  ...  ..  309 

Gen.  7.    Trichinella,  Railliet  ...             ...  ...  ...  ...  ...  311 

Trichinella  spiralis,  Owen               ...  ...  ...  ...  ...311 

History  of  the  Development  of  Trichinella  spiralis  ...  ...  314 

(/)  Fam.  Strongylidce       ...             ...             ...  ...  ...  ..  .tt  ^22 

Gen.  8.   Eustrongyhis,  Dies.  ...             ...  ...  ...  ...  ...  322 

Sp.  JEtislrongylus gigas^  Rud.          ...  ...  ...  ...  ...  332 

Gens.  9.  Slrongylus,  O.  F.  Miiller         ...  ...  ...  ...  ...  324 


CONTENTS  xi. 

THE  ANIMAL  PARASITES  OF  MAN— contd. 

Nematodes — contd.  PAGE 

Sp.  Strongylus  apri,  Gmelin  ....  ...  ..  324 

Strongylus  subtilis,  Looss  ...  ...  ..326 

Gen.  10.   Ankylostoma,  Dubini  ...  ...  ...  327 

Sp.  Ankylostoma  duodenale  ...  ..  ...  ...  327 

Uncinaria  americana,  Stil.  ...  ...  ...              ...  ...  331 

Gen.  n.   Physaloptera,  Rud.   ...  ...  ...  ...  332 

Sp.  Physaloptera  cancasica,  v.  Linstow  ...  •••333 

(g]  Fam.  Ascaridcz            ...             ...  ...  ...  ...             ...  ...  333 

Gen.  12.  Ascaris,  L.                 ...  ...  ...  ...             ...  ...  333 

Sp.  I.  Ascaris  lumbricoides  (L.)  ...  ...  ...  ...  333 

2.  Ascaris  cam's,  Werner  ...  ...  ...  ...  336 

3.  Ascaris  maritima,  Lkt.  ...  ...  ...  ...  338 

Gen.  13.   OxyuriS)  Rudolphi    ...  ...  ...  ...  ...  338 

Sp.  Oxyuris  vermicular  is  ...  ...  ...              ...  ...  338 

Gordiacea    ...              ...              ...  ...  ...  ...              ...  ...  340 

D.  Acanthocephala  (Rud.)               ...  ...  ...  ...  341 

Structure  and  Development         ...  ...  ...  ..               ...  ...  341 

Species  of  Acanthocephala  in  Man  ...  ...  ...  ...  344 

1.  Echinorhynchus gigas,  Goeze  ...  ...  ...              ...  ...  344 

2.  EchinorhyncJms  hominis,  Lambl.  ...  ...  ...  ...  344 

3.  Echinorhynchus  moniliformis  ...  ...  ..               ...  ...  345 

E.  Hirudinea,  s.  Discophora  (Leeches)  ...  ...  ...  345 

Structure          ...              ...             ...  ...  ...  ...  ...  345 

i.   Gnathobdellidce  (Leeches  with  Jaws)  ...  ...  ...             ...  ...  347 

Gen.  Hirutio,  L.        ...             ...  ...  ...  ...  ...  347 

Sp.  i.  Hirudo  medicinalis  ...  ...  ...  •'          ...  ...  347 

2.   Hirudo  troctina     ...  ...  ...  ...  347 

Gen.  Limnatis            ...              ...  ...  ...  ...  ...  348 

Sp.  3.   Limnatis  nilotica  ...  ..  ...  ...  ...  348 

Gen.  Hamadipsa,  Tennent       ...  ...  ..  ...              ...  ...  348 

2.   Rhyncobdellida  (Leeches  with  Rostrum).. ,  ...  ...  348 

Gen.  Hamentaria      ...              ...  ...  ...  ...  ...  348 

Gen.  Placobdella         ...             ...  ...  ...  ...  348 

F.  Arthropoda  (Jointed -limbed  Animals)  ...  ...  ...             ...  ...  349 

A.   Arachnoidea  (Spiders,  Mites,  &c.)  ...  ...  ...  350 

Order  Acarina           ...             ...  ...  ...  ..             ...  ...  350 

1.  Fam.  Trombidiida       ...  ...  ...  ...             ...  ...  351 

Leptus  autumnalis,  Shaw  ...  ...  ...             ...  . . .  35 1 

Trombidium  thalsahuate  ...  ...  ...             ...  •••353 

Akamushi  or  Kedani...  ...  ...  ...              ...  ...  354 

2.  Fam.  Tetranychida      ...  ...  ...  ...  ...  355 

Tetranycfms  mohstissimus  ...  ...  ...              ...  ...  355 

Tetranychus  telarius ...  ...  ...  ...  355 

3.  Fam.  Tarsonemidce      ...  ...  ...  ...  ...  356 

Pedicttloides  ventricosus  ...  ....  ...              ...  ...  356 

4.  Fam.  E-upodidce            ...  ...  ...  ...  357 

Tydeus  molestus         ...  ...  ...  ...  ...  357 

5.  Fam.  Gamasida            ...  ...  ...  ...             ...  ...  358 

Dennanyssus  gallina:  ...  ...  ..,.              ,..  ...  358 

Dermanyssus  hirundinis  ...  .  .  ...  ...  358 

Holothyrus  coccinella...           .:..  ',..  ...  ...  ...  359 

6.  Fam.  Ixodidcz                ...  ...  ...  ...  ...  360 

Classification  of  Ixodida  ... ...  ...  362 

Synopsis  of  Genera    ...  ...  ...  ...  363 


xii.  CONTENTS 

THE  ANIMAL  PARASITES  OF  MAN—  contd. 

Arthropoda— contd.  PAGE 

Ixodes  reduuitts  ...              ...  ...  ...        t      •  •  •  •  •  •  3"4 

Ixodes  hexagonus                ...  ...  •  •  •  3^6 

Amblyomma  cayennense    ...  •••  3^7 

Hyalomma  cegyptium         ...  ...  •••  3^7 

Hcemaphysalis  punctata     ...  ...  ...  368 

Dermacentor   reticulalus  ...  ..  •••  •••              •••  3^8 

Rhipicephalus  sanguineus . . .  ...  ...  •••  3^9 

Argas  reflexus     ...             ...  •••  •••  •••  3^9 

Argas  per  sicus     ...              ...  ...  ...  •••  371 

Argas  chinche     ...             ...  •••  372 

Ornithodorus  savignyi       ...  ...-  •  ••  37 2 

Ornithodorus  turicala        ...  ^_  ,•••  '  •••  •••  373- 

Ornithodorus  talaje            ...  ...  "...  -"373 

Ornithodorus  tholozani      ...  ...  .*.  •••  373 

Ornithodorus  mtgnini       . . .  '    •  •  •  •  •  •  •  •  •              •  •  •  374 

7.  Fam.    Tyroglyphida     ...  374 

Sp.  Tyroglyphus farince          ..  ...  .*.  ...  375 

Tyroglyphus  siro             ...  ...  ...  ...  375 

Tyroglyphus  longior       ...  . •  •  3 7 5 

Glyciphagus  prunorum  ...  ...  ...  ...              ...  377 

Glyctphagus  cursor          ...  ...  ...  ...             •••377 

Glyciphagus  buski           ...  ....  ,-...  •••  377 

Rhizogly phtis  parasiticus  ...  ...  ....              ...  37^ 

Histiogaster  spermaticus  ,:.:  ••••.  •«•             •>•  37§ 

Cheylettts  mericourti,  Lab.  ./,    .  ;.'.  •  ...              •••  379 

8.  Fam.  Sarcoptidce        '  ...             ...  ..„,.-  ...  ...             ...  379 

Sp.  Sarcoples  scabiei              ...  ....  ...  ...              ...  380 

Sarcoptes  minor               •••    -.  ...  r     ...              ...    383 

Nephrophages  sanguinarius  ...  ...  ...              .».  3^4 

9.  Fam.  Demodicidff        ...             ..,  ...  ...  ...             ...  385 

Demodex  folliculorum       ...  ...  ...  •..*              ...  3^ 

Order  Lingualulidce.  ...             ...           '...  ...  ...  !V«»'«             •••  3^7 

Linguatula  rhinaria     ...              ...  ..;..  .-•  ...              ...  387 

Porocephalus  conslrictus                 ...  ...  ...  ...              ...  390 

B.  Myriapoda    ...             ...             ...             ..,.  ...  ...  .,.  390 

C.  Insecta           ...             ...             ...             ...  .....  .....  '.*.  390 

Structure,  Development  and  Classification  ...    -  .*;-;,         ...  ...  391 

I.  Rhyncola                ...             ...          ,  ...  ;.  \,...  ..'.  ...              ...  394 

(a)  Rhynchola  aptera,  s.  parasilica...  ...  ...  ...              ...  394 

Fam.   Pediculida         ...            ...  ...  ..  ...             ...  394 

Sp.   I.   Pediculus  capitis       ...  ...  ...  ...             "-395 

2.  Pediculus  vestimenti  ...  ...  ...              ...     396 

3.  Phthirius  inguinahs  ...  ...  396 

(6)  Rhynchota  hemiptera  ...              ...  ...  ...  ...              ...  397 

Fam.  Acanthiadae      ...              ...  ...  ...  ...              ...  397 

Sp.  4.   Cimex lectularius      ...  ...  ...  ...  397 

5.  Cimex  ciliatus           ...  ...  ...  ...     398 

6.  Cimex  rotundat us     ...  ...  ...  ...  398 

Fam.  Reduviidcc        ...              ...  ...  ...  ...              ...  398 

Sp.   7.    Conorhinus  sanguisuga  ...  ...  ...              ...  398 

8.  Conorhinus,  sp.  novum  ...  ....  ...  399 

9.  Conorhinus  rubrofasciatus       ...  ...  ...  ...     399 

10.  Conorhinus  nnggeri  ...  ...  x,             -...  400 

11.  Conorhinus  variegatus  ...  ...  ...              ...  400 


CONTENTS  xiii. 

THE  ANIMAL  PARASITES  OF  MAN — contd. 

Arthropoda — contd.  PAGE 

12.  Conorhinus  nigrovarius  ...  ...  ...  400 

13.  C.  protractus        ...  ...  ...  ...  400 

1 4 .  Redwvius personatus  ...  ...  ...  400 

15.  Coriscus  subcoleoptratus  ...  ...             ...  ...  401 

16.  Rasahus  biguttatus  ...  ...  ...  401 

17.  Melanolestes  morio  ...  ...  ...  401 

1 8.  Melanolestes  abdominalis  ...  ...  ...  402 

Fam.  Lygaida            ...             ...  ...  ...  ...  402 

Sp.  19.  Lyctocoris  catnpestris  ...  ...             ...  ...  402 

20.   Rhodinus  prolixus  ..  ...  ...  402 

II.  Coleoptera             ...    "         ...              ...  ...  ...  ...  403 

Silvanus  surincunensis               ...  ...  ...              ...  ...  403 

III.  Diplera               ...              ...              ...  ...  ...  403 

(a)  Aphaniptera...              ...              ...  ...  ...  ...  403 

Sp.  I.   Pulex  irritans                ...  ...  ...              ...  ...  403 

2.  Sarcopsylla penetrans    ...  ...  ...  ...  405 

3.  Sarcopsylla  gallinacea  ...  ...  ...  ...  406 

4.  Pulex  serraticeps            ...  ...  ...              ...  ...  406 

5.  Pulex fasciatus              ...  ...  ...             ...  .  .  407 

6.  Ftilex  pallipes                 ...  ...  ...             ...  ...  407 

7.  Typh'.opsylla  mtisculi    ...  ...  ...  ...  407 

SYSTEMATIC,  ANATOMICAL,  AND  BIOLOGICAL  REMARKS  ON  MOSQUITOES  ...  ...  407 

Culicidae  or  Mosquitoes         ...              ..".             ...  ...  ...             ...  ...  415 

Classification  of  Culicuia      ...             ...             ...              ...  ...  ...  ...  421 

Notes  on  the  Different  Genera         ...              ...  ...  ...             ...  ...  425 

Sub-family  Anophelina          ...              ...  ...  ...              ...  ...  425 

Genus  I.  Anopheles •,  Meigen        ...              ...  ...  ...  ...  425 

Genus  2.  Myzomyia,  Blanch.  ;   Grassia,  Theob.       ...  ...  ...  425 

Genus  3.    Cycloleppteron,  Theob....             ...  ...  ...  ...  425 

Genus  4.  Stethomyia>  Theob.       ...             ...  ...  ...  ...  426 

Genus  5.   Pyretophorus,  Blanch —              ...  ...  ...  ...  426 

Genus  6.  Arribalzagia>  Theob.   ...             ...  ...  ...  ...  426 

Genus  7.  Myzorkynchust  Blanch.               ...  ...  ...  ...  426 

Genus  8.   Nyssorhynchtts^  Blanch.                ...  ...  ,..  ...  426 

Genus  9.    Cellia,  Theob.               ...  ...  ...  427 

Genus  10.  Aldrichia^  Theob.      ...             ...  ...  ...  ...  427 

Sub-family  Megarhinina       ...              ...              ...  ...     '         ...  ...  427 

Genus  II.  Megarhinus,  Robineau-Desvoidy  ...  ...  ...  427 

Genus  12.    Toxorhynchites,  Theob.             ...  ...  ...  ...  427 

Sub-family  Gulicina               ...              ...              ...  ...  427 

Genus  Muciiitis,  Theob.                ...              ...  ...  ...  427 

Genus  Psorophora,  Robineau-Desvoidy      ...  ...  ...  428 

Genus Janthinosoma,  Arribalzaga                ...  ...  ...  ...  428 

Genus  Slegoinyia,  Theobald          ...              ..  ...  ...  428 

Sp.  Stegomyia  scittellaris,  Walker       ...  ...  ...  ...  428 

Genus  Theoba!dinella>  Blanch.     ...             ...  ...  428 

Sp.  Theobaldiriella  annulata,  Meigen...  ...  ...  429 

Genus  Culex,  Linnaeus  ...              ...             ...  ...  ...  ...  429 

Genus  Melanoconion^  Theobald  ...             ...  ...  ...  ...  429 

Genus  Grabhatnia,  Theobald       ...             ...  ...  ...  ...  43° 

Genus  Taniorhynchus^  Arribalzaga            ...  ...  43° 

Genus  Mansonia,  Blanch.              ...             ...  ..  ...  ...  430 

Genus  Acartoinyia,  Theobald       ...             ...  ...  ...  431 

Other  NEMATOCERA     ...            ...            ...            ...            ...  ...  ...  ...  431 


xiv.  CONTENTS 

OTHER  NISMATOCERA — contd.  PAGE 

Sand  flies  or  Simulida           ...             ...  ...  ...  •  ••  431 

Simulium  maculatiun,  Meigen    ...  ...  ...  •••  432 

Family  Chironomida             ...  ...  ...  •••  433 

Genus  Ceratopogon         ...  ...  ...  •  ••  433 

Psychodidce  ...               ..              ...  ...  ...  434 

Brachycera  (Flies)     ...             ...  ...  434 

1.  Phfra  rtifipes,  Meig.     ...  ...  ...  •••  435 

2.  Piophila  casei  (L.)        ...  ...  435 

3.  Teichomyzafusca,  Macq.  ...  ...  435 

4.  Anthomyia  canicular  is,  Meig.  ...  ...  435 

5.  Hoiualomyia  scalar  is,  Fabri.  ...  ...  ...  436 

6.  Musca  domestica,  L,.     ...  ...  ...  ...  . .  436 

7.  Lucilia  macellaria  (Fabri.)  ...               ..  ...  ...  436 

8.  Lucilia  nobilis,  Meig.  ...  ...  ...  ...  437 

9.  Lucilia  ctzsar>  Limm.   ...  ...  ...  ...  438 

10.  Sarcophaga  carnaria  (L.)  ...               ..  ...  ...  438 

11.  Sarcophaga  magnifica  ...  ...  ...  ...  ...  438 

12.  Ochromyia  anthropophaga  ..  ...  ...              ...  ...  439 

13.  Auchmeromyia  depressa  ...  ...  ...              ...  ...  439 

14.  Auchmeromyia  luteola,  Fabr.  ...  ...  ...              ...  ...  439 

15.  Hypoderma  bovis           ...  ...  ...  ...              ...  ...  440 

16.  Hypoderma  diana         ...  ...  ...  ...              ...  ...  440 

17.  Gastrophilus,  sp.            ...  ...  ...  ...              ...  ...  440 

18.  Dermatobia  cyaniventris  ...          •    ...  ...  ...  ...  441 

19.  Dermatobia  noxialis     ...  ...  .:.  ...              ...  ...  441 

Biting-mouthed  Brachycera      ...  ...  ...  ...           '  •••  •••  442 

Family  Tabanidcz,  or  Gad-flies  ...  ...  ...  ...  442 

Family  Asilida,  or  Wolf-flies  ...  ..  ...             ...  ...  444 

Family  Muscida  (in  widest  sense)  ...  ...  ...             ...  ...  445 

Glossitia  (Tsetse-flies)  ...  ...  ..               ...  ...  446 

Pupipara,  or  Eproboscida  ...  ..  ...             ...  ...  447 


LIST   OF    ILLUSTRATIONS. 


FIG.   i.  Amceba  coli,  Loesch. 

2.  Encysted  intestinal  amoeba.     (After  Grassi.) 

3.  Amceba  colt,  Loesch.     (After  Kovacs.) 

4.  Aniceba  coli  from  a  Cat.     (After  Kovacs.) 

5.  Amceba  kartulisi,  Dofl.     (After  Kartulis.) 

6.  Amceba  miurai^  Ijima. 

7.  Leydenia  gemmipara,  Schaudinn. 

8  &  9.  Trichomonas  vaginalis.     (After  Kiinstler.) 

10.  Trichomonas  inlestinalis,  Lkt.     (After  Grassi. ) 

11.  Lambliaintestinalis.     (After  Grassi  and  Schewiakoff.) 
12  &  13.  Cercomonas  howinis.     (After  Davaine,  Lambl.) 

14.  Monas  pyophila,R.  Blanch.     (After  Grimm.) 

15.  Bodo  urinariiiS)  Kiinstler. 

16.  Flagellata  observed  by  Barrois. 

17.  Trypanosoma  lewisi,  Kent.     (After  Kempner  and  Rabinowitch.) 

18.  Trypanosoma  carasszi,  Mitrophanow. 

19.  Mo  no  cyst  is  agilis.     (After  v.  Stein.) 

20.  Xiphorhynchus  firmus,  Leger. 

21.  Clepsidrina  munieri,  Schneid.     (After  Schewiakoff.) 

22.  Conjugation  stages  of  Clepsidrina  blattarum.     (After  Butschli.) 

23.  Sporulation  stage  of, Clepsidrina  ovata.     (After  Schneider.) 

24.  Monocystis  sp.  of  earth-worms.     (After  Butschli.) 

25.  Spores  of  various  gregarines.     (After  Leger.) 

26.  Clepsidrina  lon°a.     (After  Leger. ) 

27.  Coccidium  cuniculi.     (Riv.) 

28.  Spores  of  Coccidium  cuniculi.     (After  Balbiani.) 

29.  Swarm  cysts  of  Coccidium.     (After  R.  Pfeiffer.) 

30.  Development  of  Coccidium  schubergi,  Schaudinn. 
31  &  32.  Coccidium  cuniculi  (Riv.).     (After  Balbiani.) 

33.  Coccidium  ho  minis.     (After  Riek.) 

34.  Coccidium  bigeminum,  Stiles. 

35.  Eimeria  hominis,  R.  Blanch.     (.\fterKiinstler.) 

36.  Quartan  parasite.     (After  Mannaberg  or  Golgi.) 

37.  Tertian  parasite.     (After  Mannaberg.) 
38  &  39.  Pernicious  parasite.     (After  Mannaberg.) 

40.  Development  of  pernicious  parasites  in  the  intestine  of  Anopheles  maculipennis. 

(After  Grassi.) 

41.  Ookinets  of  pernicious  parasites.     (After  Grassi.) 

42.  Cysts  of  pernicious  parasites.     (After  Grassi.) 

43.  Four   stages  of  sporulation  of  malaria  parasites  from  A.  maculipennis.      (After 

Grassi.) 

44.  Sporoz  ntes  of  pernicious  parasites.     (After  Grassi.) 
45  &  46.  Hamogregarina  stepanowi.     (After  Danilewsky. ) 

47.  Myxosporidia,  &c.     (After  J.  Miiller.) 

48.  Myxobolus  miilleri,  Butschli. 


xvi.  LIST    OF   ILLUSTRATIONS 

FlG.  49.  Myxidium  lieberkilhnii,  B.     (After  Butschli.) 

50.  Spore  of  Myxobolus.     (After  Doflein.) 

51.  Myxidimum  lieberkuhnii.     (After  L.  Cohn.) 

52.  Myxoproteus  ambiguus,  &c.     (After  Doflein.) 

53.  Spores  of  Myxosporidium.     (After  Biitschli.) 
54  &  55.  Nosema  bombycis.     (After  Balbiani,  Thelohan.) 

56,  57  &  60.     Sarcocystis  miescheriani.     (Kiihn,  Bertram.) 

58  &  59.  Sarcocystic  tenella.     (After  Bertram.) 

61.  Spores  of  S.  tenella,  Raill.     (After  Laveran  and  Mesnil.) 

62  &  63.  Balantidium  coli.     (Leuckart,  Casagrandi  and  Barbagallo.) 

64.  Balantidium  minutum.     (After  .Schaudinn.) 

65.  Nyctotherus faba,  Schaudinn. 

66.  Polystomuin  integer  rimum  of  frog.      (After  Zeller.) 

67.  Fasciola  hepatica,  L. 

68.  Harmostotnum  leptoslomum.     (Olss.) 

69.  Anterior  of  Dislomum  hepaticum. 

70.  Allocreadium  isoporum  (Looss). 

71.  Terminal  cells  of  Cotylogonimus  heterophyes.     (After  Looss.) 

72  &  73.  Male  and  female  genitals  of  Opisthiogylphe  endoloba.     (After  Looss.) 

74.  Ovum  of  Fasciola  hepatica. 

75.  Miracidium  of  Distomutn  hepaticum.     (From  Leuckart.) 

76.  Cercaria  of  Echinostomum  sp. 

77.  Development  of  Fasciola  hepatica,  L.     (From  Leuckart.) 

78.  Redia  of  liver  fluke.     (After  Leuckart.) 

79.  Redia  of  Cercaria  echinata. 

80.  Cercaria  of  liver  fluke.     (After  Leuckart.) 

81.  Encysted  Fasciola  hepatica.      (After  Leuckart.) 

82.  Gastrodiscus  hominis.     (After  Leuckart.) 
83,  84  &  85.  Fasciola  hepatica. 

86.  Egg  of  Fasciola  hepatica,  L. 

87.  Limnceus  minulus:     (From  Leuckart.) 

88.  Young  Fasciola  hepatica.     (Fiom  Leuckart,) 

89.  Fasciola  hepatica,  var.  angttsta,  Raill.     (After  Stiles  and  Hassall.) 

90.  Fasciolopsis  buski  (Lank.).     (After  Odhner.) 

91.  Dislomum  rathouisi  (Poir).     (After  Glaus.) 
92  &  93.  Paragonimus  westermani  (Kerb.). 

94.  Egg  of  Paragonimus  westermani  (Kerb.). 

95  &  98.  Opisthorchis  felinetts,  Riv. 

96.  Egg  of  Opisthorchusfelineus. 

97.  Distomum  sibiricum.     (After  Winogradoff.) 
99.  Metorchis  truncatus,  Rud. 

100  &  IOI.  Opisthorchis  sinensis,  Cobb. 

102.  Uterine  egg  and  miracidium  of  Opisthorchis  sinensis. 

103.  Opisthorchis  noverca,  Mihi.     (After  Leuckart.) 

104.  Distomum  con  June  turn  y  Cobb. 

105.  Coiylogonimus  heterophyes  (v.  Sieb. ).     (After  Looss. ) 

106.  Dicroccelium  lanceatum  (Stiles  and  Hassall.) 

107.  Eggs  of  Dicroccelium  lanceatum  (Stiles  and  Hassall). 

108.  Miracidia  of  Dicroccclium  lanceatum. 

109.  Schislosomum  hcemalobium,  Bilh.     (After  Looss.) 
no,  III  &  112.     Schistosomum  htzmalobiiim. 

113.  Ovum  of  Schistosomum  hamatobium,  Bilh. 

114.  Schistosomum  japonicum. 

115.  Section  <>f  vessel,  showing  schistosomes. 
116  &  117.  Section  of  appendix,  showing  ova. 

118.  Transverse  section  of  Ligula.     (After  Blochmnnn.) 


LIST    OF   ILLUSTRATIONS  xvii. 

FIG.   119.  Section  through  proglottis  of  Tvenia  crassicollis. 

1 20  &  121.  Rostellutn  and  head  of  Dipylidium  caninum. 

122.  Section  of  head  of  Tcenia  crassicollis. 

123.  Young  Acanthobothrium  coronatum,  v.  Ben. 

124.  Scolex  of  cysticercoid  from  Arion.     (After  Pintner.) 

125.  Proglottis  of  Tcenia  saginata. 

126.  Proglottis  of  Dibothriocephalus  latus.     (From  Glaus.) 

127.  Section  through  proglottis  of  T.  crassicollis. 

128.  Section  through  proglottis  of  Dibothriocephalus  latus. 

129.  Egg  of  Diplogonoporus  grandis.     (After  Kurimoto.) 

130.  Uterine  egg  of  T.  saginata,  G.     (After  Leuckart.) 

131.  Oncospheres  of  T.  africana.     (After  von  Linstow.) 

132.  Plerocercus  of  Tetrarhynchus. 

133.  Young  cysticerci  of  Tcenia  saginata,  G.     (From  Leuckart.) 

134.  Cysticercoid  of  Arion  ater. 

135.  Section  through  piece  of  Ccenuris  cerebralis. 

136.  Median  section  through  Cysticercus.     (After  Leuckart.) 

137.  Cysticercus  pisiform  is. 

138.  Chains  of  segments  of  Dibothriocephalus  latus. 

139.  Section  of  head  of  Dibothriocephalus  latus. 

140.  Proglottis  of  Dibothriocephalus  latus. 

141.  Egg  of  Dibothriocephalus  latus. 

142  &  143.  Oncosphere  of  Dibothriocephalus  latus.     (After  Schauinsland,  Leuckart.) 

144.  Plerocercoid  of  Dibothriocephalus  latus. 

145.  Plerocercoid  of  D.  latus  in  a  Lota  vulgaris. 

146.  Cephalic  end  of  D.  cordatus.     (After  Leuckart.) 
147  &  148.  Diplogonoporus  grandis.     (After  Kurimoto.) 

149.  Cephalic  end  of  Bothr.  mansoni,  Cobb.     (After  Leuckart.) 

150  &  151.  Dipylidium  caninum.     (After  Diamare.) 

152.  Cysticercoid  of  Dipylidium  caninum.     (After  Grassi  and  Rovelli.) 

153  &  154.  Hymenolepis  nana  (v.  Siebold). 

155.  Villus  of  rat  with  cysticercoid  of  Hymenolepis  murina.    (After  Grassi  and  Rovelli.) 

156  &  157.  Hymenolepis  diminuta. 

158.  Ovum  of  Hymenolepis  diminuta.     (After  Grassi.) 

159.  Hymenolepis  lanceolata.     (After  Goeze.) 

1 60.  Scolex  of  Davainea  madagascariensis.     (After  Blanchard.) 
161  &  162.  Tcenia  solium. 

163.  Hooks  of  T.  solium.     (After  Leuckart). 

164.  Ovum  and  embryo  of  T.  solium. 

165.  Mature  proglottides  of  T.  solium. 

1 66.  Hooklets  of  T.  marginata.     (After  Leuckart.) 
167  &  1 68.  Tcenia  saginata. 

169.  Muscle  of  ox  with  Cysticercus  bovis.     (After  Ostertag.) 

170,  171  &  172.      Tfznia  africana.     (After  v.  Linstow.) 

173  &  174.  Tcenia  confusa. 

175.  Tcenia  echinococcus. 

176.  Section  through  an  Echinococcus  cyst. 
177  &  178.  Echinococcus  veterinorum. 

179.  Echinococcus  hominis. 

180.  Hooklets  of  Echinococcus. 

181.  Echinococcus  multilocularis.     (After  Ostertag.) 
182,  184,  189  &  217.     Ascaris  lumbricoides . 

183  &  185.  Ascaris  megalocephalus.     (After  Nassonow.) 

1 86  &  1 88.  Rhabditis  form  of  Rhabdonema  nigrovenosum. 

187.  Transverse  section  through  Ascaris  mystax. 

190.  Muscle  of  pig  with  capsules  containing  Trichinae. 

B 


xviii.  LIST    OF   ILLUSTRATIONS 

FIG. 

191  &  192.  Strongyloides  intestinalis. 

193.  Gnathostotna  siamense.     (After  Levinson.) 

194,  1940  &  I94<£.     Guinea- worm  or  Filaria  medinensis.     (After  Leuckart.) 

195.  Filaria  immitis.     (After  Railliet.) 

196.  Mouth  organs  of  mosquito  piercing  skin  of  dog.     (After  Noe). 

197.  Larvae  of  Filaria  bancrofti.     (After  Railliet.) 

198.  Filaria  magalhdesi.     (After  v.  Linstow.) 
199  &  200.  Filaria  loa.     (After  R.  Blanchard.) 

20 1  &  202.  Filaria  conjunctive.     (After  Addario,  Grassi.) 

203  &  204.  Filaria  equina.     (After  Railliel). 

205.  Trichocephalus  trichiurtts. 

206.  Trichinella  spiralis.     (After  Glaus.) 

207.  Trichinella.     (After  Her  twig-Graham.) 
208  &  209.  Calcification  of  Trichinella. 

210.  Eustrongylas  gigas.     (After  Railliet.) 

211.  Eggs  of  Eustrongylas  gigas.     (After  Railliet.) 

212.  Strongyhis  apri.     (After  Railliet.) 
213,  214  &  216.     Ankylostotna  duodenah. 

215.  Ovum  of  Ankylostoma  duodenale.     (After  Parona  and  Grassi.) 

217.  A  scan's  liunbricoides.     (From  Glaus.) 

218.  Ovum  of  A  scar  is  lumbricoides. 

219.  Section  through  head  -part  of  Ascaris  canis.     (After  Leuckart.) 

220.  Ovum  of  Ascaris  cants, 
221  &  222.  Oxyuris  vermicularis . 

223.  Echinorhynchus  angustatus. 

224.  Echinorhynchus  acus.     (After  Wagener. ) 

225.  Egg  of  Echinorhynchus  gigas.     (After  Leuckart.) 

226.  The  internal  organs  of  the  leech.     (After  Kennel.) 

227.  Hirudo  medicinalis.     (After  Glaus.) 
228  &  229.  Leptus  autumnalis. 

230.  The  Kedani  mite.     (After  Tanaki.) 

231.  Tetranychus  telarius>  var.  russeolus,  Koch.     (After  Artault.) 

232.  Pediculoides  ventricosiis.     (After  Laboulbene  and  Megnin.) 

233.  Tydeus  molestus.     (After  Moniez.) 

234.  Dermanyssus  gallince.     (After  Berlese.) 

235.  Dermanyssus  hirundinis.     (After  Delafond.) 
236  &  237.  Ixodes  ricinus.     (After  Pagenstecher.) 

238.  Argas  reflexus.     (After  Pagenstecher.) 

239.  Argas  per sicus.     (After  Megnin.) 

240.  Tyroglyphns farince.     (After  Berlese.) 

241.  Tyroglyphus  longior,  Gerv.     (After  Fum.  and  Robin.) 

242.  Rhizoglyphus  parasiticus.     (After  Dalgetty.) 
243  &  244.  Sarcoptes  scabiei.     (After  Fiirstenberg.) 

245.  Sarcoptes  minor.     (After  Railliet.) 

246  &  247.  Nephrophages  sanguinarius.     (After  Miyake  and  Scriba. 

248.  Demodex  folliculorum  of  the  dog.     (After  Megnin.) 

249  &  250.  Linguatula  rkinaria. 

251  &  254.  Pediculus  vestimenli,  Burm. 

252.  Ovum  of  the  head -louse. 

253.  Head-louse,  male. 

255.  Phthirius  inguinalis^  Leach. 

256.  Head  of  the  bed-bug. 

257.  Pulex  irritans. 

258.  Larva  of  flea.     (After  Railliet.) 

259.  Pulex  serraticeps. 

260  &  261.  Sarcopsylla penetrans.     (After  Moniez.) 


LIST   OF   ILLUSTRATIONS  xix. 

FIG.  262.  Head  of  male  and  female  Anopheles.     (After  Giles.) 

263.  Head  of  male  and  female  Culex.     (After  Giles). 

264.  Mouth-parts  of  A.  claviger.     (After  Grassi.) 

265.  Anopheles  maculipennis .     (After  Nuttall  and  Shipley.) 

266.  Longitudinal  section  of  an  A nopheles.     (After  Grassi.) 

267.  Anopheles  maculipennis,  Meigen.     (After  Grassi.) 

268.  Larva  of  A.  maculipennis,  Fabr.     (After  Grassi.) 

269.  Larva  of  Culex.     (After  Grassi.) 

270.  Pupa  of  A.  maculipennis^  Meig.     (After  Grassi.) 

271.  Neuration  of  wing.     (Theobald.) 

272.  Heads  of  Culex  and  Anopheles.     (After  Daniels.) 

273.  Eggs  of  various  mosquitoes. 

274.  Diagram  of  structure  of  typical  mosquito.     (Theobald.) 

275.  Types  of  scales;  head  and  scutellar  ornamentation  ;  forms  of  clypeus.     (Theobald.) 

276.  Wing  of  Anopheles  maculipennis^  Meigen. 

277.  Wing  of  a  Culex. 

278.  Wing  of  Simulium. 

279.  Wing  of  Chironomus. 

280.  A  Ceratopogon  or  Midge. 

281.  An  owl  midge  (Phleboiomus,  sp.).     (Giles.) 

282.  Larva  of  Ant  homy  ia  canicularis. 

283.  Larvae  of  Mtisea  vomitaria. 

284.  Larva  of  Lucilia  macellaria. 

285.  The  Screw-worm  fly  (Compsomyia  macellaria}.     (After  Conel.) 

286.  Green  bottle-fly  (Lucilia  ccesar,  Linn.) 

287.  Larva  of  Ochromyia.     (After  Blanchard.) 

288.  Larva  of  Dermatobia  cyaniventris.     (After  Blanchard.) 

289.  Larva  of  Dermatobia  cyaniventris.     (After  Blanchard.) 

290.  Dermatobia  noxialis,  Goudot. 

291.  Ox  gad-fly  (Tabanus  bovinus.  Linn.). 

292.  The  Brimp  (Hamatopota pluvialis.  Linn.). 

293.  Stinging  fly  (Stomoxys  calcitram,  Linn.). 

294.  Tsetse-fly  (Glossina  morsitans}  (West wood). 


ON    PARASITES    IN   GENERAL. 


BY  the  term  PARASITES  is  understood  living  organisms  which, 
for  the  purpose  of  procuring  food,  take  up  their  abode,  temporarily 
or  permanently,  on  or  within  other  living  organisms.  There  are 
both  plants  and  animals  (Phytoparasites  and  Zooparasites)  both  of 
which  lead  a  parasitic  life  in  or  upon  other  plants  and  other 
animals. 

Phytoparasites  are  not  included  in  the  following  descrip- 
tions of  the  forms  of  parasitism,  but  a  very  large  number  of  animal 
parasites  (zooparasites)  are  described ;  the  number  of  the  latter,  as 
a  rule,  are  very  much  under-rated.  How  great  a  number  of  animal 
parasites  exist  may  be  gathered  from  the  fact  that  with  the  excep- 
tion of  the  Echinodermata  and  the  Tunicata,  which,  so  far  as  we  know 
at  present,  do  not  harbour  living  parasites,  all  other  classes  of  animals 
are  subject  to  them  ;  some  of  the  larger  classes,  such  as  Sporozoa, 
Cestodes,  Trematodes  and  Acanthocephala,  consist  entirely  of  para- 
sitic species,  and  parasitism  even  occurs  amongst  the  vertebrates 
(Myxine).  It  therefore  follows  that  the  characteristics  of  parasites 
lie,  not  in  their  structure,  but  in  the  manner  of  their  existence. 

Parasitism  itself  occurs  in  various  ways  and  degrees.  Accord- 
ing to  R.  Leuckart,  we  should  distinguish  between  OCCASIONAL  (tem- 
porary) and  PERMANENT  (stationary)  PARASITISM.  Occasional  para- 
sites, such  as  the  flea  (Pulex  irritans),  the  bed-bug  (Cimex  lectularia), 
the  leech  (Hirudo  medicinalis),  and  others  only  seek  their  "  host  " 
to  obtain  nourishment  and  find  shelter  while  thus  occupied,  but 
without  being  bound  to  the  host,  they  usually  abandon  the  latter 
soon  after  the  attainment  of  their  object  (Cimex,  Hirudo),  or  they 
may  remain  on  the  body  of  their  host  throughout  their  entire  develop- 
ment from  the  hatching  of  the  egg  (Pulex).  It  follows  from  this  mode 
of  living  that  the  occasional  parasites  become  sometimes  distinguish- 
able from^Blir  free-living  relatives,  though  only  to  a  slight  extent. 
It  is,  therefore,  never  difficult  to  assign  the  systematic  position  of 
temporary  parasites  from  their  structure. 


2  THE   ANIMAL   PARASITES   OF    MAN 

In  consequence  of  their  mode  of  life  all  these  forms  live  on 
the  external  surface  of  the  body  of  their  host,  though  more  rarely  they 
take  up  their  abode  in  cavities  easily  accessible  from  the  exterior, 
such  as  the  mouth,  nose  and  gills.  They  are  therefore  frequently 
called  EPIZOA  or  ECTOPARASITES  ;  but  these  designations  do  not 
only  cover  the  temporary  parasites,  because  numerous  epizoa  (as 
for  instance  the  louse)  are  parasitic  during  their  entire  life. 

In  contradistinction  to  these  temporary  parasites,  the  permanent 
parasites  obtain  shelter  as  well  as  food  from  their  host  for  a  long 
period,  sometimes  during  the  entire  course  of  their  life  ;  they  do  not 
seek  their  host  only  when  requiring  nourishment,  but  always  remain 
with  him,  thus  acquiring  essential  protection.  The  permanent  para- 
sites, as  a  rule,  live  within  the  internal  organs,  preferably  in  those 
which  are  easily  accessible  from  the  exterior,  such  as  the  intes- 
tine, with  its  appendages ;  nevertheless,  permanent  parasites  are 
also  found  in  separate  organs  and  systems,  such  as  the  muscular 
and  vascular  systems,  hollow  bones,  brain,  &c. :  some  live  on  the 
outer  skin.  Here,  again,  the  terms  ENTOZOA  and  endoparasites  do 
not  include  all  stationary  parasites  ;  to  the  latter,  for  instance, 
appertain  the  lice,  which  pass  all  their  life  on  the  surface  of  the  body 
of  their  host,  where  they  find-  shelter  and  food  and  go  through  their 
entire  development.  The  ectoparasitic  trematodes,  numerous  insects, 
crustaceans,  and  other  animals  live  in  the  same  manner. 

All  "  HELMINTHES,"  however,  belong  to  the  group  of  permanent 
parasites.  This  term  is  now  applied  to  designate  certain  low  worms 
which  lead  a  parasitic  life  (intestinal  worms)  ;  but  they  are  not 
all  so  termed.  For  instance,  the  few  parasitic  TURBELLARIA  are  never 
classed  with  the  helminthes,  although  closely  related  to  them.  The 
turbellarians,  in  fact,  belong  to  a  group  of  animals  of  which  only  a 
few  members  are  parasitic,  whereas  the  helminthes  comprise  those 
groups  of  worms  of  which  all  species  (Cestodes,  Trematodes,  Acantho- 
•cephala),  or  at  least  the  majority  of  species  (Nematodes),  are  para- 
sitic.  Formerly  the  Linguatulidse  (Pentastomum)  were  classed  with 
the  helminthes  because  their  existence  is  also  endoparasitic,  and 
because  the  shape  of  their  body  exhibits  a  great  similarity  to  that  of 
the  true  helminthes ;  but  since  the  study  of  the  development  of 
the  Linguatulidse  (P.  J.  van  Beneden,  1848,  and  R.  Leuckart,  1858) 
has  demonstrated  that  they  are  really  degenerated  arachnoids,  they 
have  been  separated  from  the  helminthes. 

It  is  hardly  necessary  to  emphasise  the  fact  that  the  helminthes 
or  intestinal  worms  do  not  represent  a  systematic  group  of  animals, 
but  only  a  biological  one,  and  that  the  helminthes  can  only  be  dis- 


PERMANENT    PARASITISM  3 

cussed  in  the  same  sense  as  one  speaks  of  land  and  water  animals, 
i.e.,  without  conveying  the  idea  of  a  classification  in  such  a  grouping. 
It  is  true  that  formerly  this  was  universally  done,  but  very  soon  the 
error  of  such  a  classification  was  recognised :  still,  until  the  middle  of 
last  century,  the  helminthes  were  regarded  as  a  systematic  group, 
although  C.  E.  v.  Baer  (1827)  and  F.  S.  Leuckart  (1827)  strenuously 
opposed  this  view.  Under  the  active  leadership  of  J.  A.  E.  Goeze, 
J.  G.  H.  Zeder,  J.  G.  Bremser,  K.  A.  Rudolfi  and  F.  Dujardin,  the 
knowledge  of  the  helminthes  (helminthology)  developed  into  a  special 
study,  but  unfortunately  it  lost  all  connection  with  zoology.  It 
required  the  intervention  of  Carl  Vogt  to  disestablish  the  helminthes 
as  one  class  of  animals,  by  uniting  the  various  groups  with  those  of 
the  free-living  animals  most  closely  related  to  them  (Platy helminthes, 
Nemathelminthes). 

PERMANENT  PARASITISM  has,  in  the  course  of  time,  caused 
creatures  adopting  this  mode  of  life  to  undergo  considerable,  some- 
times even  striking,  bodily  changes,  permanent  ectoparasites  having 
as  yet  undergone  least  alteration.  The  latter  sometimes  bear  so 
unmistakably  the  likeness  to  that  group  to  which  they  belong  that 
even  a  superficial  knowledge  of  their  structure  and  appearance 
often  suffices  for  the  recognition  of  their  systematic  position.  For 
instance,  though  the  louse  has,  like  many  decidedly  temporary 
parasites,  lost — a  characteristic  of  insects — its  wings  in  consequence 
of  parasitism,  yet  nobody  would  deny  its  insect  nature  (Cimex, 
Pulex).  On  the  other  hand,  however,  the  changes  in  a  number  of 
permanent  ectoparasites  (such  as  parasitic  Crustacea)  are  far  more 
considerable,  and  correspond  with  the  changes  that  have  taken 
place  in  permanent  endoparasites. 

These  alterations  depend,  partly  on  retrogression  and  .partly  on 
the  acquisition  of  new  peculiarities  ;  in  the  former  case  the  change 
consists  in  the  loss  of  those  organs  which  have  become  useless  in  a 
permanent  parasitic  condition  of  existence,  such  as  wings  in  the 
louse,  and  the  articulated  extremities  seen  in  the  larval  stage  of 
parasitic  crustaceans.  The  loss  of  these  organs  goes  hand  in  hand 
with  the  cohesion  of  segments  of  the  body  that  were  originally 
separate,  and  alterations  in  the  muscular  and  nervous  systems.  In 
the  same  manner  another  means  of  locomotion  is  lost — the  ciliated 
coat — which  is  possessed  by  many  permanent  parasites  during  their 
larval  period,  and  which  is,  to  all  appearances,  not  secondary  and 
recently  acquired,  but  represents  a  primary  character  inherited 
from  free-living  progenitors,  and  still  transmitted  to  the  altered 
descendants,  because  of  use  during  the  larval  stage  (the 


4  THE   ANIMAL   PARASITES   OF   MAN 

larvse  of  a  great  many  Trematodes,  the  oncospheres  of  some 
Cestodes).  Amongst  the  retrogressions,  the  loss  of  the  organs  of 
sense  may  be  mentioned,  particularly  the  eyes,  which  are  still 
present,  not  only  in  the  nearest  free-living  forms  but  also  in 
the  free-living  larvae  of  true  parasites  ;  it  is  only  quite  excep- 
tionally that  the  eyes  are  subsequently  retained  ;  as  a  rule  they  are 
lost.  Lastly,  in  a  great  many  cases  the  digestive  system  also 
disappears,  as  in  parasitic  crustaceans,  in  a  few  nematodes  and 
trematodes,  in  all  cestodes  and  acanthocephala.  There  remains  at 
most  the  rudiments  of  the  muscles  of  the  foregut,  but  these  are 
adapted  to  entirely  different  uses. 

The  new  characters  which  permanent  parasites  may  acquire 
are,  first  of  all,  the  remarkably  manifold  CLASPING  and  CLINGING 
ORGANS,  which  are  seldom  (as  in  parasitic  crustaceans)  directly 
joined  on  to  already  existing  structures.  In  those  instances  in 
which  organs  for  the  conveyance  of  food  are  retained,  these  likewise 
frequently  undergo  transformation,  in  consequence  of  the  altered 
food  and  manner  of  feeding ;  such  alterations  consist,  for  instance, 
in  the  transformation  of  a  masticating  mouth  apparatus  into  the 
piercing  and  sucking  organs  of  parasitic  insects. 

HERMAPHRODITISM  (as  in  Trematodes,  Cestodes,  and  a  few  Nema- 
todes) is  a  further  peculiarity  of  many  permanent  parasites  ;  moreover, 
the  living  together  in  couples  that  occurs,  especially  in  trematodes, 
may  lead  to  complete  cohesion  and,  exceptionally,  also  to  re-separation 
of  the  sexes.  In  many*  cases  the  females  only  are  parasitic,  while 
the  males  live  a  free  life,  or  there  may  be  in  addition  the  so-called 
complementary  males.  Occasionally  the  male  alone  is  parasitic,  and 
in  that  case  lives  within  the  female  of  the  same  species,  which  may 
live  free,  like  certain  Gephyrea  (Bonellia),  or  the  female  also  may 
be  parasitic,  as  Trichosomum  crassicaudum,  which  lives  in  the  bladder 
of  the  sewer  rat  (Mus  decumanus). 

We  have  numerous  proofs  that  demonstrate  how  considerably 
the  original  features  of  many  parasites  have  become  changed.  We 
need  only  draw  attention  to  the  aforementioned  Linguatulidae,  also  to 
many  of  the  parasitic  crustaceans  belonging  to  various  orders.  In 
all  of  these  a  knowledge  of  the  larval  stages — in  which  there  is  no 
alteration,  or  at  most  only  a  slight  degree  of  change — serves  to 
determine  their  systematic  position,  i.e.,  the  nearest  conditions  of 
relationship. 

The  most  remarkable  changes  are  observed  in  those  groups  that 
contain  only  a  few  parasitic  members,  the  majority  leading  a  free 
life.  A  striking  instance  is  afforded  by  a  snail,  the  well-known  Enlo- 
concha  mirabilis,  Miiller.  This  mollusc  consists  merely'of  an  elongated 


HERMAPHRODITISM  5 

sac  living  in  a  Holothurian  (Synapta  digit  ata),  which  possesses  none 
of  the  characteristics  of  either  the  gastropods  or  any  molluscs,  and  in 
the  interior  of  which  there  is  nothing  to  be  observed  but  the  organs 
of  generation  and  the  embryos.  Nevertheless,  the  Entoconcha  is 
decidedly  a  parasitic  snail,  as  is  clearly  proved  by  its  larvae,  but 
it  is  a  snail  which,  in  consequence  of  parasitism,  has  lost  all  the 
characteristics  of  molluscs  in  its  mature  condition,  but  still  exhibits 
them  in  the  early  stages  of  development. 

Certain  nematodes  show  very  clearly  to  what  devious  courses 
parasitism  may  lead.  The  Atractonema  gibbosum,  the  life-history  of 
which  has  been  described  by  R.  Leuckart,  and  which  lives  in  the 
larvae  and  pupae  of  a  dipterous  insect  (Cecidomyia),  exhibits,  in  its 
early  stage,  the  ordinary  characteristics  of  other  threadworms.  A 
few  weeks  later — the  males  having  died  off  immediately  after  copu- 
lation— the  females  are  transformed  into  spindle-shaped  bodies,  the 
mouth  and  anus  of  which  are  closed.  They  carry  with  them  an  irregu- 
larly shaped  appendage,  in  which  the  segmenting  ova  are  situated 
and  in  which  the  further  conditions  of  life  of  the  Atractonema  are 
accomplished.  A  minute  examination  has  demonstrated  that  this 
appendage  is  the  prolapsed  and  enlarged  vagina  of  the  creature  which 
has  become  merely  a  supplementary  attachment.  The  conditions 
present  in  the  Sphaerularia,  the  nematoid  nature  of  which  was  long 
undiscovered,  are  still  more  remarkable.  It  was  only  when  Siebold 
proved  that  typical  nematodes  were  hatched  from  their  eggs 
that  their  nature  was  recognised.  The  nematodes  thus  produced 
have  not  the  slightest  resemblance  to  the  parent. 

The  researches  of  Lubbock,  A.  Schneider,  and  more  particularly 
of  R.  Leuckart,  have  shown  that  what  we  call  Sphaerularia  bombiis  not 
an  animal  but  merely  an  organ — the  vagina — of  a  nematode  worm. 
This  vagina  at  first  grows,  sac-like,  from  the  body  of  the  tiny  nema- 
tode ;  it  gradually  assumes  enormous  dimensions,  (2  cm.  in  length)  ; 
it  contains  the  sexual  organs  and  parts  of  the  intestine  ;  the  remain- 
ing portion  of  the  actual  creature  then  becomes  small  and  shrivelled  ;• 
it  may  be  easily  overlooked,  being  but  an  appendage  to  the  vagina 
with  its  independent  existence,  and  it  finally  disappears  altogether. 

The  GREAT  FERTILITY  of  parasites  is  another  of  their  peculiarities, 
though  this  may  be  also  the  case  to  a  certain  degree  with  some  of 
the  free-living  animals,  the  progeny  of  which  are  likewise  exposed 
to  enormous  destruction. 

More  remarkable,  however,  is  the  fact  that  the  young  of  the 
endoparasites  only  very  exceptionally  grow  to  maturity  by  the  side 
of  their  parents  ;  for  they  always  sooner  or  later  leave  the  organ 


6  THE   ANIMAL   PARASITES   OF   MAN 

inhabited  by  the  latter,  almost  always  reach  the  open,  and  after  a 
shorter  or  longer  period  of  free  existence  seek  new  hosts.  During 
their  free  period,  moreover,  a  considerable  growth  may  be  attained, 
or  metamorphosis  may  take  place,  or  even  procreation.  In  the 
exceptional  cases  in  which  the  young  remain  within  the  same  host, 
they  nevertheless  always  quit  the  organ  inhabited  by  the  parents. 
They  likewise  NEVER  attain  maturity  within  the  host  inhabited  by 
the  parents,  but  only,  as  in  other  cases,  after  having  gained  access 
into  fresh  hosts. 

These  transmigrations  play  a  very  important  role  in  the  natural 
history  of  the  internal  parasites,  but  they  frequently  conceal  the  cycle 
of  development,  for  sometimes  there  are  INTERMEDIARY  GENERATIONS, 
which  themselves  invade  intermediary  hosts.  Even  when  there  are  no 
intermediary  generations,  THE  SYSTEM  OF  THE  INTERMEDIARY  HOSTS 
is  frequently  maintained  by  the  endoparasites. 

According  to  the  kind  of  food  partaken  of  by  parasites,  it  has 
recently  become  usual  to  separate  the  true  parasites  from  those 
creatures  that  feed  on  the  superfluity  of  the  food  of  the  host,  or  on 
products  which  are  no  longer  necessary  to  him,  and  to  call  the  latter 
MESSMATES  or  commensals.  As  examples,  the  Ricinidae  are  thus 
designated,  because,  like  actual  lice,  they  dwell  amongst  the  fur  of 
mammals  or  the  plumage  of  birds  ;  they  do  not,  however,  suck 
blood,  for  which  their  mouth  apparatus  is  unsuited,  but  subsist 
on  useless  epidermal  scales.  These  epizoa,  according  to  J.  P.  van 
Beneden,  are,  to  a  certain  extent,  useful  to  their  hosts,  by  removing 
deciduous  materials  which  under  certain  circumstances  might  become 
harmful  to  them.1  This  investigator,  who  has  contributed  so  greatly 
to  our  knowledge  of  parasites,  assigns  the  Ricines  to  the  MUTUALISTS, 
under  which  term  he  comprises  animals  of  various  species  which 
live  in  common,  and  confer  certain  benefits  on  one  another.  The 
mutualists  are  usually  intimately  connected  in  a  mutually  advan- 
tageous association  known  as  "  symbiosis."2 

Incidental  and  Pseudo-parasites. — In  many  cases  the  parasites  are 
confined  to  certain  hosts,  and  may  therefore  be  designated  as  specific 
to  such  hosts.  Thus,  hitherto,  Tcenia  solium  and  Tcenia  saginata 
in  their  adult  condition  have  only  been  found  in  man ;  Tcenia  crassi- 


1  The  Ricinidae  are  by  no  means  advantageous  to  their  hosts.     These  Hemipterous 
parasites  give  rise  to  an  intolerable  itching  which  may  cause  loss  of  rest,  emaciation, 
and  sometimes  even  death.     Birds  suffering  from  phthiriasis  of  the  Ricines  are  usually 
in  bad  health.— L.  W  S. 

2  For  further  information  on  these  conditions,  see  Die  Schmarotzer  des  Thierreichs, 
by  P.  J.  van  Beneden,  Leipzig,  1876  ;  and  Die  Symbiose,  by  O.  Hertwig. 


INCIDENTAL   AND    PSEUDO-PARASITES  7 

colis  only  in  the  cat ;  Distomum  turgidum  and  D.  ovocaudatum  only 
in  Rana  esculenta,  and  so  forth.  In  many  other  cases,  however, 
certain  species  of  parasites  are  common  to  several,  and  sometimes 
many,  species  of  hosts ;  Tcznia  cucumerina  s.  elliptica  is  found  in 
the  domestic  cat  as  well  as  in  the  dog ;  Distomum  hepaticum  is  found 
in  a  large  number  of  herbivorous  mammals  (nineteen  species),  Am- 
phistomum  subclavatum  in  numerous  urodela  and  anuric  amphibia, 
Holostomum  variabile  in  about  twenty-four  species  of  birds,  and  so 
on.  In  these  cases  the. hosts  are  almost  invariably  closely  related, 
appertaining,  as  a  rule,  to  the  same  family  or  order,  or  at  any  rate 
to  the  same  class.  Trichina  spiralis,  which  is  found  in  man,  and 
in  the  bear,  pig,  rat,  mouse,  cat,  fox,  polecat  and  marten,  and  is 
capable  of  being  artificially  cultivated  in  the  dog,  rabbit,  sheep,  horse 
and  in  other  mammals,  and  even  in  birds,  is  one  of  the  most 
striking  exceptions. 

Some  parasites  are  so  strictly  confined  to  one  species  of  host  that, 
even  when  artificially  introduced  into  animals  very  closely  related 
to  their  normal  host,  they  do  not  thrive,  but  sooner  or  later,  often 
very  quickly,  die  off,  and  very  rarely  establish  themselves.  For 
example,  repeated  attempts  have  been  made  to  rear  the  adult 
Tcenia  solium  in  the  dog,  or  to  rear  Cysticercus  cellulose  in  the  ox, 
or  Cysticercus  Tcenia  *  saginata  in  the  pig,  but  they  have  always 
proved  unsuccessful ;  only  exceptionally  has  it  been  possible  to 
transfer  Ccenurus  cerebralis,  the  larval  stage  of  a  tapeworm  of  the 
dog  (Tcznia  ccenurus),  from  the  brain  of  the  sheep  to  that  of  the 
domestic  goat.  On  the  other  hand  in  the  case  of  the  Trichinae 
transference  into  a  different  host  is  easily  accomplished. 

Under  natural  conditions  it  is  not  uncommon  for  certain  kinds  of 
specific  parasites  to  occur  occasionally  in  unusual  hosts ;  they  there 
stand  to  the  latter  as  "  INCIDENTAL  PARASITES."  Thus  Echinorhynchus 
gigas,  a  specific  parasite  of  the  pig,  is  only  an  incidental  parasite  of 
man  ;  Distomum  hepaticum  and  Distomum  lanceolatum  are  specific  to 
numerous  kinds  of  mammals,  but  may  be  found  incidentally  in  man ; 
on  the  other  hand,  Bothriocephalus  lotus,  a  specific  parasite  of  man, 
may  occasionally  take  up  its  abode  in  the  dog,  cat  and  fox.  As  a 
rule  all  those  parasites  of  man  that  are  only  rarely  met  with,  not- 
withstanding that  human  beings  are  constantly  being  observed  and 
examined  by  medical  men,  are  termed  INCIDENTAL  PARASITES  OF  MAN. 
In  many  cases  we  are  acquainted  with  the  normal  or  specific  host 
of  these  parasites.  Thus  we  know  the  specific  host  of  Balantidium 
coli,  Coccidium  oviforme,  Distomum  hepaticum,  T&nia  cucumerina,  &c.  ; 
in  others  it  is  as  yet  unknown  to  us.  In  the  latter  case  the  question 


8  THE   ANIMAL   PARASITES   OF   MAN 

partly  relates  to  such  forms  as  have  been  so  deficiently  described 
that  their  recognition  is  impossible,  partly  to  parasites  of  man  in 
various  regions  of  the  earth,  the  Helminthes  and  parasites  of  which 
are  totally  unknown  or  only  slightly  known,  or  finally  to  early  develop- 
mental stages  that  are  difficult  to  identify.  Creatures  that  usually 
live  free,  and  exceptionally  become  parasitic,  may  likewise  be  called 
incidental  parasites.  In  this  category  are  included  a  few  Anguillulidce 
that  have  been  observed  in  man ;  also  Leptodera  appendiculata, 
which  usually  lives  free,  but  may  occasionally  become  parasitic 
in  black  slugs  (Arion  empiricorum)  :  when  parasitic  it  attains  a 
larger  size,  and  produces  far  more  eggs  than  when  living  a  free  life. 
In  order  to  avoid  errors,  the  term  "  incidental  parasites  "  should  be 
confined  to  true  parasites  which,  besides  living  in  their  normal  host, 
may  also  live  in  other  hosts.  Leuckart  speaks  of  FACULTATIVE  PARA- 
SITISM in  such  forms  as  Leptodera.1  L.  Oerley  succeeded  in  artifi- 
cially causing  Rhabditis  pellio  to  assume  facultative  parasitism  by 
introducing  these  worms  into  the  vagina  of  mice,  where  the  parasites 
remained  alive  and  multiplied.  Rhabditis  pellio  dies  in  the  intestines 
of  mammals  and  man  ;  it  remains  alive  in  frogs,  but  always  escapes 
into  the  open  with  the  faeces. 

Recently  the  incidental  parasites  of  man  have  also  been  called 
"  PSEUDO-PARASITES  "  or  "  PSEUDO-HELMINTHES  "  ;  formerly,  how- 
ever these  terms  were  applied  not  only  to  living  organisms  that  do 
not  and  cannot  live  parasitically,  and  that  only  exceptionally  and 
incidentally  get  into  man,  but  also  to  any  foreign  bodies,  portions 
of  animals  and  plants,  or  even  pathological  formations  that  left  the 
human  system  through  the  natural  channels,  and  the  true  nature 
of  which  was  misunderstood.  Frequently  these  bodies  were  described 
as  living  or  dead  parasites  and  labelled  with  scientific  names,  as  if 
they  were  true  parasites.  A  study  of  these  errors,  which  formerly 
occurred  very  frequently,  would  be  as  interesting  as  it  would  be 
instructive.  It  is  better  not  to  use  the  expression  pseudo-parasites 
for  incidental  parasites,  but  to  keep  to  the  original  meaning,  for  it 
is  not  at  all  certain  that  pseudo-parasites  are  not  described,  even 
nowadays. 

The  Influence  of  Parasites  on  the  Host. — In  a  great  many  cases 
we  are  not  in  a  position  to  state  anything  regarding  any  marked 
influence  exercised  by  the  parasite  on  the  organism  and  on  the  con- 
ditions of  life  of  the  host.  Most  animals  and  many  persons  exhibit 
no  signs  of  such  influence.  As  a  general  rule,  the  parasite,  which  is 
always  smaller  and  weaker  than  its  host,  does  not  attempt  to 

1  Oerley,  L.,   Die  Rhabditiden  und  ihre  medicinische  Bedeutung,  Berlin,  1886,  p.  65. 


THE    INFLUENCE   OF   PARASITES  9 

endanger  the  life  of  the  latter,  as  simultaneously  its  own  existence 
would  be  threatened.  The  parasite,  of  course,  robs  its  host,  but 
usually. in  a  scanty  and  sparing  manner,  and  the  injuries  it  inflicts 
can  hardly  be  taken  into  account.  There  are,  however,  numerous 
cases  in  which1  the  situation  of  the  parasites  or  the  nature  of  their 
food,  added  to  their  number  and  movements,  may  cause  more  or 
less  injury,  and  even  threaten  the  life  of  the  host.  It  stands  to 
reason  that  a  Cysticercus  cellulosce  situated  in  the  skin  is  of  but  slight 
importance,  whereas  one  that  has  penetrated  the  eye  or  the  brain 
must  give  rise  to  serious  disorders.  A  cuticular  or  intestinal  parasite 
is,  as  a  rule,  less  harmful  than  a  blood  parasite.  A  helminth,  such 
as  an  Ascaris  lumbricoides  or  a  tapeworm,  that  feeds  on  the  residues 
of  foodstuffs  within  the  intestine,  will  hardly  affect  its  host  by 
depriving  it  of  this  material.  The  case  is  different  when  the  parasites 
are  very  numerous,  especially  when  the  heavily  infested  host  happens 
to  be  a  young  individual  needing  all  it  ingests  for  its  own  require- 
ments, and  therefore  unable  to  sustain  the  drain  of  numerous  guests 
in  the  intestine.  Disturbances  also  set  in  more  rapidly  when  the 
intestinal  helminthes  are  blood-suckers,  such  as  Anchylostoma  duo- 
denale,  the  injury  to  the  host  resulting  from  the  kind  of  food  taken 
by  the  parasite. 

Generally,  the  disorders  caused  by  loss  of  chyle  are  insignificant 
when  compared  with  those  induced  by  the  GROWTH  and  agglomera- 
tion of  the  helminthes  ;  the  latter  may  cause  chiefly  obstructions  of 
small  vessels  or  symptoms  of  pressure  in  affected  or  contiguous 
organs,  with  all  those  complications  which  may  arise  secondarily, 
or  they  may  even  lead  to  the  complete  obliteration  of  the  organ 
attacked.  Of  course  the  symptoms  will  vary  according  to  the  nature 
of  the  organ  attacked. 

In  consequence,  also,  of  the  MOVEMENTS  of  the  parasites,  disorders 
are  set  up  that  may  tend  to  serious  pathological  changes  of  the 
affected  organs.  The  collective  migrations,  undertaken  chiefly  by  the 
embryos  of  certain  parasites  (trichinosis,  acute  cestode  tuberculosis),  / 
are  still  more  harmful,  as  are  also  the  unusual  migrations  of  other 
parasites,  which,  incidentally,  may  lead  to  the  formation  of  so-called 
worm  abscesses  or  to  abnormal  communications  (fistulae)  between 
organs  that  are  contiguous  but  possess  no  direct  connection. 

Recently,  several  authors  have  called  attention  to  the  fact  that 
the  helminthes  produce  MATERIALS  that  are  TOXIC  to  their  host ;  and 

1  Liihe,  M.,  "  Ueber  d.  Fix.  d.  Helm.  a.  d.  Darmivand  ihrer  Wirthe  u.  die  dadurch 
verursachten  path.-anat.  Ver  Under  itngen  d.  Wirthsdarmes,"  Trans,  of  the  IV.  Intern. 
Zool.  Congr.,  Berlin,  1901. 


10  THE   ANIMAL   PARASITES    OF    MAN 

the  effects  of  such  poisons  explain  the  pathology  of  helminthiasis 
far  more  satisfactorily  than  the  theory  of  reflex  action. 

In  a  number  of  cases  these  toxic  materials  (leucomaines)  have 
been  isolated  and  their  effects  on  living  organisms  demonstrated 
by  actual  experiments.  It  also  appears  that  the  absorption  of 
materials  formed  by  the  decomposition  of  dead  helminthes  may 
likewise  cause  toxic  effects.  However,  our  knowledge  of  these  con- 
ditions is  as  yet  in  its  initial  stage.1 

Nearly  all  the  symptoms  caused  directly  or  indirectly  by  para- 
sites are  of  such  a  nature  that  the  presence  of  the  parasites 
cannot  be  diagnosed  with  any  certainty,  or  only  very  rarely ;  the 
most  that  can  be  done  is  to  deduce  the  presence  of  parasites  by  the 
exclusion  of  other  causes.  Fortunately,  however,  there  are  sufficient 
means  by  which  we  may  confirm  the  diagnosis  in  a  great  many  cases. 
Such  means  consist  not  only  in  a  minute  examination  of  the  patient 
by  palpation,  percussion  and  local  inspection,  but  also  in  the  micro- 
scopical examination  of  the  natural  secretions  and  excretions  of  the 
body,  such  as  sputum,  nasal  mucus,  urine  and  fseces.  Though  such 
examinations  may  entail  loss  of  time,  they  are  necessary  in  the  interest 
of  the  patient.  It  appears  to  me,  moreover,  that  quackery,  which  has 
gained  considerable  ground  even  in  the  treatment  of  the  helminthic 
diseases  of  man,  can  thus  be  considerably  limited. 

Origin  of  Parasites. — In  former  times,  when  the  only  correct  views 
that  existed  related  to  the  origin  of  the  higher  animals,  the  mode 
of  procreation  of  the  parasites  as  well  as  of  other  low  animals 
was  ascribed  to  SPONTANEOUS  GENERATION  (generatio  cequivoca),  and 
this  opinion  prevailed  throughout  the  middle  ages  ;  the  writers  on 
natural  science  merely  devoted  their  time  to  the  interpretation  of  the 
views  of  the  old  authors,  and  perpetuated  the  opinion  of  the  ancients 
on  questions  which  even  in  those  days  could  have  been  correctly 
explained  merely  by  observation. 

It  was  only  when  observations  were  again  recommenced,  and  the 
microscope  was  invented,  that  the  idea  of  spontaneous  generation 
became  limited  ;  not  only  did  the  microscope  reveal  the  organs  of 
generation  or  their  products  (eggs)  in  numerous  animals,  but,  Redi 
succeeded  in  proving  that  the  so-called  Helcophagi  (flesh  maggots)  are 

1  Moursson,  et  Schlagdenhauffen,  " Nouv.  reck.  din.  et  phys.  sur  quelq.  liquides  organ.," 
C.  R.  Ac.,  Paris,  1882,  p.  791  ;  Debove,  "  De  I'intox.  hydat.,"  Bull,  et  Mem.  soc.  m,'d.  des 
hopit.,  1888  ;  Linstow,  v.,  "Ueb.  d.  Giftgehalt  d.  Helm.,"  Internat.  Monatsschr.  /.  Anat.  u. 
Phys.,  xiii.,  1896  ;  Peiper,  "Z.  SymptomatoL  derthier.  Paras.,"  Deutsche  med.  Wochenschr., 
1897,  No.  40;  Mingazzini,  P.,  "  Ric.  sul.  veleno  d.  elm.  int.,"  Rass.  intern,  d.  med. 
modern.  Ann.,  ii.,  1901,  No.  6  ;  Vaullegeard,  A.,  "Etud.  exp.  et  crit.  sur  V  action  d.  helm." 
Bull.  soc.  Linn,  de  Normandie,  5,  Ser.  T.  vii.,  1901,  p.  84,  and  others. 


ORIGIN   OF   PARASITES  II 

only  the  progeny  of  flies,  and  never  appear  in  the  flesh  of  slaughtered 
animals  when  fully  developed  flies  are  prevented  from  approaching 
and  depositing  their  eggs  on  it.  Swammerdam  likewise  knew 
that  the  "  worms  "  living  in  the  caterpillars  of  butterflies  were  the 
larvae  of  other  insects  (Ichneumon  flies)  which  had  laid  their  eggs  in 
their  bodies  ;  he  also  discovered  the  ova  of  lice.  The  two  authors 
mentioned  were,  however,  unwilling  to  see  the  experience  they  had 
gained  regarding  insects  applied  to  the  helminthes,  while  Leeuwen- 
hoek  vehemently  opposed  the  theory  of  a  spontaneous  generation, 
maintaining  that,  on  a  basis  of  common  sense,  eggs,  or  at  all  events 
germs,  must  exist,  even  though  they  could  not  be  seen. 

The  use  of  the  microscope  also  revealed  a  large  number  of  very 
small  organisms  in  the  water  and  moist  soil,  some  of  which  undoubtedly 
resembled  helminthes.  Considering  the  wide  dissemination  of  these 
minute  organisms,  it  was  natural  to  conjecture  that  after  their  almost 
unavoidable  introduction  into  the  human  system  they  should  grow 
into  helminthes  (Boerhave,  Hoffmann).  Linnaeus  went  even  further, 
for  he  traced  the  descent  of  the  liver-fluke  of  sheep  from  a  free-living 
planaria  (Dendroccelum  lacteum),  the  Oxyuris  vermicularis,  from  free- 
living  nematodes,  and  the  Tcenia  lata  (i.e.,  Bothriocephalus  latus) 
from  a  tapeworm  (Schistocephalus  solidus)  found  free  in  the  water. 
Linnaeus'  statements  met  with  general  approval.  However,  we 
must  bear  in  mind  that  at  that  time  the  number  of  helminthes 
known  was  very  small,  and  many  of  the  forms  that  we  have  long 
ago  learned  to  differentiate  as  specific  were  then  regarded  as  of  ONE 
SPECIES.  Linnaeus'  statements  were  partly  supported  by  similar  dis- 
coveries by  other  investigators,  such  as  Unzer,  and  partly  also  by 
the  discovery  of  eggs  in  many  helminthes.  It  was  believed  that  the 
eggs  hatched  out  in  the  outer  world  gave  birth  to  free-living  creatures, 
and  that  these,  after  their  introduction  into  the  intestine,  were  trans- 
formed into  helminthes.  By  means  of  these  eggs  the  old  investigators 
tried  to  explain  the  HEREDITARY  TRANSMISSION  of  the  intestinal 
worms,  which  was  universally  believed  until  the  commencement  of 
the  last  century ;  some  authors  went  so  far  as  to  regard  the  intes- 
tinal worms  as  congenital  or  inherited  ;  they  maintained  the  possi- 
bility of  direct  transmission,  as  in  suckling,  and  denied  that  the  eggs 
reaching  the  external  world  had  anything  to  do  with  the  propagation 
of  the  parasites. 

The  more  minute  comparison  between  the  supposed  free-living 
stages  of  the  helminthes  and  their  adult  forms,  and  the  impossibility 
of  finding  corresponding  free  forms  for  the  ever-increasing  number 
of  parasitic  species,  revealed  the  improbability  of  Linnaeus'  state- 


12  THE    ANIMAL  PARASITES   OF    MAN 

ments  (O.  Fr.  Miiller).  It  was  the  latter  author  also  who  recognised 
the  origin  of  the  tapeworms  (Schistocephalm,  Ligula)  found  free  in 
the  water.  They  originate  from  fishes  which  they  quit  spontaneously. 

Nevertheless,  and  in  spite  of  the  fact  that  van  Doeveren  and 
Pallas  correctly  recognised  the  significance  of  the  eggs  in  the  trans- 
mission of  intestinal  worms,  these  statements  remained  disregarded, 
as  did  Abildgaard's  observation,  experimentally  confirmed,  that  the 
(immature)  cestodes  from  the  abdominal  cavity  of  sticklebacks  become 
mature  in  the  intestines  of  aquatic  birds.  However,  at  the  end  of 
the  eighteenth  and  the  commencement  of  the  nineteenth  centuries, 
and  after  helminthology  had  been  raised  to  a  special  branch  of  study 
by  the  successful  results  of  the  investigations  of  numerous  authors, 
'(Goeze,  Bloch,  Pallas,  Miiller,  Batsch,  Rudolphi,  Bremser),  many 
of  whom  experienced  a  "divine  joy"  in  searching  the  intestines  of 
animals  for  helminthes,  some  authors  reverted  to  generatio  cequivoca, 
without,  however,  entirely  denying  the  existence  of  organs  of  genera- 
tion and  eggs.  The  fact  that  a  few  nematodes  bore  living  progeny 
— a  fact  of  which  Goeze  was  already  aware — had  no  influence  on 
the  erroneous  opinion,  as  in  such  cases  it  was  considered  that  the 
young  continued  to  develop  beside  the  old  forms  ;  there  were  also 
many  helminthes  known  that  never  developed  sexual  organs  and 
never  produced  eggs,  and  which  therefore  were  referred  to  generatio 
tequivoca.  People  were  convinced  that  the  intestinal  mucous  mem- 
brane or  an  intestinal  villus  could  transform  itself  into  a  worm, 
either  in  a  general  morbid  condition  of  the  body,  or  in  pathological 
changes  of  a  more  local  character.  The  appearance  of  helminthes 
was  even  regarded  as  useful  and  as  a  means  for  the  expulsion  of 
injurious  matter. 

These  views,  firmly  rooted  and  supported  by  such  eminent 
authorities  as  Rudolphi  and  Bremser,  could  not  easily  be  overthrown. 
First,  a  change  took  place  in  the  knowledge  of  the  trematodes. 
In  1773  O.  Fr,  Miiller  discovered  the  Cercarice  living  free  in  the 
water  ;  he  regarded  them  as  independent  creatures  and  gave  them 
the  name  that  is  still  used  at  the  present  time.  Nitszch,  who  also 
minutely  studied  these  creatures  and  who  recognised  the  resemblance 
of  the  anterior  part  of  their  bodies  to  a  Distomum,  did  not,  however, 
arrive  at  a  correct  conclusion ;  he  regarded  the  combination 
rather  as  that  of  a  Distomum  with  a  Vibrio,  for  which  he  mistook  the 
characteristic  tail  of  the  cercaria ;  he  also  noticed  the  encystment 
(transformation  into  the  pupa)  on  foreign  bodies  of  many  species  of 
these  creatures,  but  was  of  opinion  that  this  process  signified  only 
the  termination  of  life. 


ORIGIN   OF    PARASITES  13 

Considerable  attention  was  attracted  to  the  matter  when 
Bojanus  first  published  a  paper  entitled  "  A  Short  Note  on  Cercaria 
and  their  Place  of  Origin."  He  pointed  out  that  the  cercaria  creep 
out  of  the  "  royal  yellow  worms,"  which  occur  in  freshwater  snails 
(Linnceus  paludina),  and  are  probably  generated  in  these  worms. 

Oken,  in  whose  journal,  I  sis,  Bojanus  published  his  disco  very , 
remarks  in  an  annotation,  "  One  might  lay  a  wager  that  these  cercaria 
are  the  embryos  of  distomes."  Soon  after  (1827),  C.  E.  v.  Baer  was 
able  to  confirm  Bojanus'  hypothesis  that  the  cercaria  as  a  "  hetero- 
genous  brood  "  originated  from  spores  in  parasitic  tubes  in  snails 
(germinating  tubes).  Moreover,  Mehlis  (Isis,  1831,  p.  190)  not  only 
discovered  the  lids  of  the  ova  of  distomes,  but  likewise  saw  an  infu- 
sorian-like  embryo  slip  out  of  the  eggs  of  Monostomum  flavum  and 
Distomum  hians.  A  few  years  later  (1835)  v.  Siebold  observed  the 
embryos  (miracidia)  of  the  Monostomum  mutabile,  and  discovered  in 
their  interior  a  cylindrical  body  that  behaved  like  an  independent 
being  ("  necessary  parasite  "),  and  was  so  similar  in  appearance 
to  the  "  royal  yellow  worms  "  (Bojanus)  that  Siebold  considered  the 
origination  of  the  latter  from  the  embryos  of  trematodes  as  at  all 
events  possible.  Meanwhile,  v.  Nordmann  (Helsingfors)  had  in  1832 
seen  the  miracidia  of  distomes  provided  with  eyes  swimming  in 
water ;  v.  Siebold  (1835)  had  observed  the  embryos,  or  oncospheres, 
of  tape-worms  furnished  with  six  hooklets  in  the  so-called  eggs  of 
the  taenia  ;  while  Creplin  (1837)  had  discovered  the  "  infusorial  " 
young  of  the  Bothriocephalus  ditremus,  and  conjectured  that  similar 
embryos  were  to  be  found  in  other  cestodes  with  operculated  eggs. 
The  fact  was,  at  all  events,  established  that  the  progeny  of  the  hel- 
minthes  appears  in  various  forms  and  is  partly  free-living.  The 
researches  of  Eschricht  (1841)  were  likewise  of  influence,  as  they 
elucidated  the  structure  of  the  Bothriocephali,  and  proved  that  the 
encysted  and  sexless  helminthes  were  merely  immature  stages. 

J.  J.  Steenstrup  (1842)  was,  however,  the  first  to  furnish  explana- 
tions for  the  numerous  isolated  and  uncomprehended  discoveries. 
Commencing  with  the  remarkable  development  of  the  Coelenterata, 
he  established  the  fact  that  the  Helminthes,  especially  the  endopara- 
sitic  trematodes,  multiply  by  means  of  alternating  and  differently 
formed  generations.  Just  as  the  polyp  originating  from  the  egg 
of  a  medusa  represents  a  generation  of  medusae,  so  does  the  germinal 
tube  (royal  yellow  worm)  originating  from  the  ciliated  embryo  of  a 
distomum,  &c.,  represent  the  cercaria ;  these  were  consequently 
regarded  as  the  progeny  of  trematodes,  and  Steenstrup,  guided  by 
his  observations,  conjectured  that  the  cercaria,  whose  entrance  into 


14  THE   ANIMAL    PARASITES    OF   MAN 

the  snails  he  had  observed  accompanied  by  the  simultaneous  loss  of 
the  propelling  tail,  finally  penetrate  into  other  animals,  in  which  they 
become  distomes. 

Part  of  this  hypothetical  cycle  of  development  was  erroneous,  and 
in  other  particulars  positive  observation  was  lacking,  but  the  path 
pursued  was  in  the  right  direction.  Immediately  after  the  appear- 
ance of  Steenstrup's  celebrated  work,  v.  Siebold  expressed  his  opinion 
that  the  encapsulated  distomes  certainly  had  to  travel,  i.e.,  to  be 
transmitted  with  their  bearers  into  other  hosts,  before  becoming 
mature.  This  view  was  experimentally  confirmed  by  de  Filippi,  La 
Valette  St.  George  (1855),  as  well  as  by  Pagenstecher  (1857),  while 
the  metamorphosis  of  the  ciliated  embryo  of  distoma  into  a  germinal 
tube  was  first  seen  by  G.  Wagener  (1857)  in  Distomum  cygnoides  of 
frogs.  All  that  we  have  subsequently  learned  from  the  works  of 
numerous  investigators  about  the  development  of  endoparasitic 
trematodes  has  certainly  increased  our  knowledge  in  various  direc- 
tions, and,  apart  from  the  deviating  development  of  the  Holostomides 
has,  as  a  whole,  confirmed  the  briefly  sketched  cycle  of  development. 

Steenstrup's  work  on  the  cestodes  did  not  attract  the  same 
attention  as  his  work  on  trematodes.  Steenstrup  always  insisted 
on  the  "  nurse "  nature  of  the  cysticerci  and  other  bladder- 
worms.  Abildgaard  (1790),  as  well  as  Creplin  (1829  and  1839), 
had  already  furnished  the  information  that  certain  sexless  cestodes 
(Schistocephalus  and  Ligula)  from  the  abdomen  of  fishes  only 
become  mature  after  their  transference  into  the  intestine  of 
aquatic  birds,  and  these  passive  migrations  were  confirmed  in  an 
entire  series  of  other  cestodes,  particularly  by  v.  Siebold  (1844, 
1848,  1850)  and  E.  J.  van  Beneden  (1849),  not  by  actual  experi- 
ment, but  by  undoubted  observation. 

It  was  conjectured  correctly  that  the  ova  or  oncospheres  pene- 
trate into  certain  intermediate  hosts,  in  which  they  develop  into 
unsegmented  larvae.  Here  they  remain  until,  with  their  host,  they  are 
swallowed  by  some  predacious  animal ;  they  then  attain  the  intestine 
freed  from  the  surrounding  membranes  through  the  process  of  diges- 
tion, and  settle  themselves  there  to  form  the  adult  chain  of  proglot- 
tides.  Though  some  few  scientists,  such  as  P.  J.  van  Beneden  and 
Em.  Blanchard,  deduced  from  these  observations  that  the  bladder- 
worms  (Cystici),  which  had  hitherto  been  regarded  as  a  separate 
class  of  helminthes,  were  only  larval  taeniae,  this  correct  view  was 
not  at  first  universally  accepted  ;  the  foundation  was  too  slight, 
and  v.  Beneden  was  of  opinion  that  the  cysticerci  were  not 
necessary,  but  only  appeared  incidentally. 


ORIGIN   OF   PARASITES  15 

v.  Siebold  was  a  strenuous  opponent  to  this  theory,  notwith- 
standing his  experiences  on  the  change  of  hosts  of  the  Tetra- 
rhynchus.  Together  with  Dujardin  he  conjectured  that  the  taeniae 
underwent  a  deviating  cycle  of  development  (1850)  ;  he  was  of 
opinion  that  the  six-hooked  oncospheres  left  the  intestine,  in 
which  the  older  generation  lived,  and  were  scattered  about  with 
the  faeces,  and  finally  re-entered  per  os  (i.e.,  with  water  and  food) 
a  host  similar  to  the  one  they  had  left,  in  the  intestine  of  which 
they  were  directly  transformed  into  tapeworms.  A  changing  of 
host  in  the  sense  of  the  other  cestodes  was  not  supposed  to  occur 
(the  history  of  the  cestodes  was  at  this  time  not  entirely  estab- 
lished). As  the  oncospheres  of  the  taenia  are  enveloped  in  one 
calcareous  or  several  softer  coverings  which  they  cannot  leave 
actively,  and  as,  in  consequence  of  this  condition,  innumerable 
oncospheres  cannot,  penetrate  into  an  animal,  and  others  cannot 
reach  the  proper  animal,  v.  Siebold  conceded,  at  least  for  the 
latter,  the  possibility  of  a  further  development  ;  but  this  was  only 
supposed  to  occur  because  they  had  either  invaded  wrong  hosts, 
or,  having  reached  the  right  hosts,  had  penetrated  organs  unsuit- 
able to  their  development^  and  had  thus  gone  astray  in  their 
travels,  and  had  become  HYDROPICALLY  DEGENERATED  T^NI^E. 
This  was  v.  Siebold's  explanation  of  bladder-worms.  Naturally, 
v.  Siebold  himself  conjectured  that  a  recovery  of  the  diseased 
tapeworm  might  occur,  in  a  few  exceptional  cases,  after  trans- 
mission into  the  correct  host,  as,  for  instance,  in  the  Cysticercus  fascio- 
laris  of  mice,  the  host  of  which  is  the  domestic  cat,  and  in 
which  there  is  a  seemingly  normally  developed  piece  of  tape- 
worm situated  between  the  caudal  vesicle  and  the  cysticercus  head. 

Guided  by  correct  views,  F.  Kiichenmeister  undertook  in  Zittau 
the  task  of  confirming  the  metamorphosis  of  Cysticercus  pisiformis 
of  hares  and  rabbits  into  tapeworms  in  the  intestine  of  the  dog, 
by  means  of  feeding  experiments.  The  first  reports  on  the 
subject,  published  in  1851,  were  not  likely  to  meet  with  universal 
approval,  because  Kuqhenmeister  first  diagnosed  the  actual  tape- 
worm he  had  been  rearing  as  Tcenia  crassiceps,  .afterwards  as 
Tcenia  serrata,  and  finally  as  Tcenia  pisiformis,  n.  sp.  However, 
in  any  case  Kiichenmeister,  by  means  of  the  reintroduction  of 
experimental  investigation,  rendered  a  great  service  to  helminthology. 

The  publication  of  Kiichenmeister's  works  induced  v.  Siebold 
to  undertake  similar  experiments  (1852  and  1853),  which  were 
partly  published  by  his  disciple  Lewald  in  1852.  But  the  posi- 
tive results  obtained  hardly  changed  Siebold's  opinion,  for 


l6  THE    ANIMAL   PARASITES    OF    MAN 

although  he  no  longer  considered  the  bladder-worms  as  hydropic- 
ally  degenerated  tapeworms,  he  still  regarded  them  as  taeni^e 
that  had  strayed.  This  change  of  opinion  was  partly  due  to  an 
important  work  of  the  Prague  zoologist,  v.  Stein  (1853),  who  was  able 
to  examine  the  development  of  a  small  bladder-worm  in  the  larvae 
of  the  well-known  meal-worm  (Tenebrio  molitor),  and  to  demonstrate 
that,  as  Goeze  had  already  proved  in  the  case  of  Cysticercus  fasciolaris 
of  mice,  first  the  caudal  vesicle  is  formed  and  then  the  scolex, 
whereas  Siebold  believed  that  in  bladder-worms  the  posterior  end  of 
the  scolex  was  formed  first,  and  that  this  posterior  end  underwent  a 
secondary  hydropic  degeneration. 

In  opposition  to  v.  Siebold,  Kuchenmeister  successfully  proved 
the  necessity  of  the  bladder-worm  stage  by  rearing  tapeworms 
in  dogs  from  the  Cysticercus  tenuicollis  of  domestic  mammals 
and  from  the  Ccenurus  cerebralis  of  sheep.  He,  and  simulta- 
neously several  other  investigators  independently,  succeeded,  with 
material  provided  by  Kuchenmeister,  in  rearing  the  Ccenurus 
cerebralis  in  sheep  from  the  oncospheres  of  the  Tcenia  ccenurus 
of  the  dog  (1854).  R.  Leuckart  obtained  similar  results  in  mice 
by  feeding  them  with  the  mature  proglottides  of  the  Tcenia 
crassicollis  of  cats  (1854). 

Kuchenmeister  also  repeatedly  reared  the  Tcenia  solium  of 
man  from  the  Cysticercus  cellulosce  of  pigs  (1855),  and  from  the 
embryos  of  this  parasite  P.  J.  van  Beneden  succeeded  in  obtain- 
ing the  same  Cysticercus  in  the  pig  (1854).  As  Kuchenmeister 
had  taught  to  distinguish  the  Tcenia  mediocanellata,  known  to 
Goeze  as  Tcenia  saginata,  amongst  the  large  taeniae  of  man  (1851), 
it  was  not  long  before  R.  Leuckart  (1862)  succeeded  in  rearing 
the  cysticercus  of  the  hookless  tapeworm  in  the  ox.  It  is 
particularly  to  this  last-named  investigator  that  helminthology  is 
indebted  more  than  to  any  other  author.  He  followed  the 
gradual  metamorphosis  from  oncospheres  to  cystic  worms  in  all  its 
details. 

In  view  of  all  the  researches  that  were  made  and  which  are  too 
numerous  to  mention  individually,  the  idea  that  bladder-worms  are 
abnormal  or  only  incidental  forms  had  to  be  abandoned.  Every- 
thing points  to  the  fact  that  in  all  cestodes  the  development  is 
divided  between  two  kinds  of  animals  ;  in  one — the  host,  the  adult 
tapeworm  is  found  ;  while  in  the  other,  the  intermediary  host,  we 
find  some  form  or  other  of  an  intermediate  stage  (cysticercus  in 
the  broadest  sense).  The  practical  application  of  this  knowledge 
is  self-evident.  If  no  infected  pork  or  beef  is  partaken  of,  no 


ORIGIN    OF    PARASITES  17 

tapeworm  can  be  acquired,  and  also  the  rearing  of  cysticerci  in 
one's  own  body  is  prevented  by  avoiding  the  introduction  of  the  eggs 
of  tapeworms. 

Though  these  results  were  definitely  proved  by  numerous 
researches,  yet  they  have  been  repeatedly  challenged,  notably  by 
J..  Knoch  (1862)  who,  on  the  'basis  of  experiments,  sought  to 
confirm  a  direct  development  without  an  intermediary  host  and 
ciliated  stage,  at  all  events  as  regards  Bothriocephalus  latus. 
However,  the  repeated  communications  of  this  author  met  with 
but  little  favour  from  competent  persons,  partly  because  the 
experiments  were  conducted  very  carelessly,  and  partly  because 
their  repetition  on  dog  and  man  (R.  Leuckart)  had  no  results 
(1863).  It  was  only  in  1883  that  I  was  able  to  prove  that  the 
developmental  cycle  of  Bothriocephalus  latus  is  similar  to  that  of 
the  other  cestodes.  The  results  obtained  in  other  places  by 
Parona,  Grassi,  Ijima  and  Zschokke  render  any  discussion  of 
Kuchenmeister's  conclusions  unnecessary.  Long  after  Knoch  a 
French  author,  P.  Megnin,  also  pleaded  for  the  direct  develop- 
ment of  some  cestodes,  and  especially  some  taeniae ;  he  also  sought 
to  prove  a  genetic  connection  between  the  hookless  and  armed 
tapeworms  of  mammals  (1879),  but  the  arguments  he  adduced, 
so  far  as  they  rest  on  observations,  can  be  easily  refuted  or 
attributed  to  misinterpretation.  Only  one  of  -these  'arguments  is 
correct,  namely,  that  the  number  of  the  species  of  taeniae  with 
which  we  are  acquainted  is  far  larger  than  that  of  the  corresponding 
cystic  forms ;  but  this  disparity  alone  cannot  be  taken  as  a  proof 
of  direct  development.  We  can  only  say  that  our  knowledge  in  this 
respect  is  deficient ;  as  a  matter  of  fact,  we  have  during  recent 
years  become  acquainted  with  a  large  number  of  cystic  forms 
hitherto  unknown  appertaining  to  taeniae  which  have  long  been 
known.  It  must  also  be  borne  in  mind  that  no  man  in  his  lifetime 
can  complete  an  examination  for  bladder-worms  of  the  large  number 
of  insects,  for  instance,  which  may  destroy  an  entire  generation 
of  an  insectivorous  species  of  bird  within  a  small  district. 

Naturally  it  does  not  follow  that  direct  development  in  the 
cestodes  is  altogether  lacking,  but  the  arguments  so  far  advanced 
point  only  to  its  being  possible.  Indeed,  communications  from 
Grassi  (1889)  have  furnished  us  in  Tcenia  murina  with  an  example 
which  shows  that  development  may  take  place  without  an  inter- 
mediary host,  notwithstanding  the  retention  of  the  cystic  stage.  We 
can  no  longer  doubt  that  the  oncospheres  of  this  species,  introduced 
into  rats  of  a  certain  age,  after  a  time  grow  into  tapeworms  without 


1 8  THE   ANIMAL   PARASITES    OF   MAN 

leaving  the  intestine,  but  not  directly,  for  they  bore  into  the 
intestinal  wall,  where  they  pass  the  cystic  stage,  the  cysts  after- 
wards falling  into  the  intestinal  lumen,  where  they  develop  into 
tapeworms. 

Important  observations  were  soon  made  on  the  remaining 
groups  of  helminthes.  The  discussion  on  the  origin  of  para- 
sites soon  became  confined  to  the  helminthes.  Amongst  the 
Nematodes,  it  had  long  been  known  that  encapsulated  forms 
existed  that  had  at  first  been  regarded  as  independent  species, 
but  very  soon  they  were  pronounced  to  be  immature  forms, 
in  consequence  of  their  lack  of  sexual  organs.  Though  Dujardin 
and  also  v.  Siebold  regarded  them  as  "  strayed  "  animals, 
v.  Stein  (1853)  very  promptly  demonstrated  that  the  progeny 
of  the  nematodes  were  destined  to  travel  by  discovering  a 
perforating  organ  in  the  larval  nematodes  of  the  mealworm. 
This  was.  first  experimentally  confirmed  (1860)  by  R.  Leuckart,  R. 
Virchow  and  Zenker,  all  of  whom  succeeded  not  only  in  bringing  to 
maturity  the  muscle  trichinae  (known  since  1830)  in  the  intestine 
of  the  animals  experimented  upon,  but  were  likewise  able  to 
follow  the  migrations  of  the  progeny.  Of  course,  the  encapsu- 
lating brood  remained  in  the  same  organism,  and  in  this  respect 
deviated  from  the  broods  of  other  helminthes  which  escape  into 
the  outer  world  and  find  their  way  into  other  animals,  but  the 
encapsulated  nematodes  could  no  longer  be  regarded  as  the  result 
of  straying.  Subsequently,  R.  Leuckart,  more  or  less  completely, 
worked  out  the  history  of  the  development  of  numerous  nematodes, 
or  pointed  out  the  way  in  which  further  investigations  should  be 
made.  We  have  learnt  that  in  nematodes,  far  more  frequently 
than  in  other  helminthes,  the  typical  course  of  development  is 
subject  partly  to  curtailment  and  partly  to  complications,  which 
sometimes  considerably  increase  the  difficulties  of  investigation 
and  have  hitherto  prevented  us  from  reaching  a  definite  conclusion, 
though  the  way  to  it  is  now  clear. 

In  a  similar  manner  the  works  of  R.  Leuckart  have  cleared 
up  the  development  of  the  Acanthocephala  and  Pentastomes.  Of 
course,  much  still  remains  to  be  done ;  so  far,  we  do  not  even 
know  all  the  helminthes  of  man  and  of  the  domestic  animals  in 
all  their  phases  of  life,  and  still  less  is  known  of  those  of  other 
animals.  We  are  indebted  to  the  discoveries  of  the  last  fifty 
years  for  the  knowledge  arrived  at,  though  comparatively  few 
names  are  connected  with  it ;  the  gross  framework  is  revealed, 
but  the  gaps  only  have  been  filled  up  here  and  there.  However, 


ORIGIN    OF    PARASITES  IQ 

we  may  trustfully  leave  the  completion  of  the  whole  to  the 
future,  without  fear  that  any  essential  alterations  will  take  place. 

The  deductions  to  be  drawn  are  as  follows  :  That  the 
helminthes  like  the  ectoparasites  multiply  by  sexual  processes, 
that  the  entire  course  of  development  of  the  helminthes  is 
never  gone  through  in  the  same  host  as  is  the  case  with  several 
ectoparasites,  that  the  progeny  at  an  earlier  or  later  stage  of 
development,  as  eggs,  embryos  or  larvae,  quit  the  host  inhabited 
by  the  older  generation,  and  almost  always  attain  the  outer 
world  :  only  in  Trichinella  does  the  development  take  place  directly 
in  the  definite  host.  Where  the  eggs  have  not  yet  developed  they  go 
through  the  embryonic  evolution  in  the  outer  world,  and  the 
young  larvae  are  transmitted,  either  still  enclosed  within  the 
egg  or  embryonic  covering,  into  the  intermediary  host — more 
rarely  they  are  transferred  straight  into  the  final  host — or  they 
hatch  out  from  their  envelopes,  and  after  a  longer  or  shorter  period 
of  free  life,  during  which  they  may  partake  of  food  and  grow, 
they,  as  before,  penetrate,  usually  in  an  active  way,  into  an 
intermediary  host,  or  at  once  invade  the  final  host.  Exception- 
ally (Rhabdonema),  during  the  free  life  there  may  be  a  propaga- 
tion of  the  parasitic  generation,  and  in  this  case  only  the 
succeeding  generation  again  becomes  parasitic,  and  then  at 
once  reaches  its  final  host.  The  young  forms  which  have  invaded 
the  final  host  become  mature  in  the  latter,  .or  after  a  longer  or 
shorter  period  of  parasitism  again  wander  forth  (as  the  (Es- 
trides,  Ichneumonides,  &c.),  and  reach  the  adult  stage  in  the 
outer  world.  The  young  stages,  during  which  they  undergo 
metamorphoses  or  are  even  capable  of  producing  one  or  several 
intermediate  generations,  are  passed  in  the  intermediary  hosts 
until,  as  a  rule,  they  are  passively  carried  into  the  final  host 
and  there  complete  their  cycle  of  development  with  the  formation 
of  the  organs  of  generation.  This  manner  of  development,  the 
spending  of  life  in  two  different  kinds  of  animals  (intermediary 
and  final  host),  is  typical  of  the  helminthes.  This  is  manifested 
in  the  acanthocephala,  the  cestodes,  the  majority  of  the  endo- 
parasitic  trematodes,  a  number  of  the  nematodes,  and  the 
linguatulidae  ;  there  are  now  and  then  exceptions,  however,  in 
which,  for  instance,  the  host  and  intermediary  host  exchange  order 
(Trichinella,  Tcenia  murina). 

Parasites  are  hardly  ever  inherited  amongst  animals.  According 
to  a  few  statements,  however,  Trichinella  and  Ccenurus  are  sup- 
posed to  be  transmissible  from  the  infected  mother  to  the  foetus  ; 


20  THE    ANIMAL   PARASITES    OF    MAN 

otherwise  all  animals  acquire  their  parasites,  especially  the  entozoay 
from  without,  the  parasites  penetrating  either  actively,  as  in 
animals  living  in  the  water,  or  passively  with  food  and  drink. 
A  particular  predisposition  to  worms  is  not  more  likely  than  a 
spontaneous  origin  of  parasites. 

Derivation  of  Parasites. — Doubt  now  no  longer  exists  as  to  the 
derivation  of  the  temporary  and  of  many  of  the  stationary 
ectoparasites  from  free-living  forms.  This  conclusion  is  founded 
on  the  circumstance  that  not  only  are  there  numerous 
intermediate  degrees  in  the  manner  of  living  and  feeding 
between  predacious  and  parasitic  animals,  but  that  there  is 
more  or  less .  uniformity  in  their  structure.  The  differences  that 
exist  are  easily  explained  as  consequences  of  altered  conditions  of 
life.  The  case  is  more  difficult  in  regard  to  groups  that  are 
exclusively  parasitic  (Cestoda,  Trematoda,  Acanthocephala,  Lingua- 
tulidcz,  and  Sporozoa),  or  groups  that  are  chiefly  parasitic  (Nematoda), 
because  in  these  cases  the  gulf  that  divides  these  forms  from 
free-living  animals  is  wider.  It  is  true  that  we  know  that  the 
nearest  relatives  of  the  Linguatulidce  are  found  amongst  the 
Arachnoidea,  and  indeed  in  the  Acarina  ;  that,  moreover,  the 
structure  and  development  of  the  Sporozoa  refers  them  to  the 
Protozoa,  and  allows  them  to  be  regarded  as  the  descendants  of 
the  lowest  Rhizopodce.  We  know  that  the  Trematoda,  and  through 
these  the  Cestoda,  are  closely  related  to  the  Turbellaria,  from 
which  they  may  be  traced ;  the  Nematoda,  however,  and  still 
more  the  Acanthocephala,  stand  quite  apart.  This  is  less  evident 
however,  in  the  Nematoda,  for  there  are  numerous  free-living 
kinds  of  these  from  which  it  is  possible  that  the  parasitic 
species  may  have  descended.  Indeed,  this  seems  more  than 
probable  if  one  takes  into  consideration  such  examples  as  Lepto- 
dera,  Rhabdonema  and  Strongyloides,  as  well  as  the  conditions  of 
life  of  free-living  nematodes.  These  mostly,  if  not  exclusively, 
spend  their  lives  in  places  where  decomposing  organic  substances 
are  present  in  quantities ;  some  species  attain  maturity  only  in 
such  localities,  and  there  propagate  very  rapidly.  Should  the 
favourable  conditions  for  feeding  be  changed  the  animals  seek 
out  other-  localities,  or  they  remain  in  the  larval  form  for 
some  time  until  more  favourable  conditions  set  in.  It  is  com- 
prehensible that  such  forms  are  very  likely  to  adopt  a  parasitic 
manner  of  life  which  at  first  is  facultative  (Leptodera,  Anguillula), 
but  may  be  regarded  as  the  transition  to  true  parasitism.  The 
great  advantages  attached  to  a  parasitic  life  consisting  not  only 


DERIVATION    OF   PARASITES  21 

in  protection,  but  also  in  the  supply  of  suitable  food,  and  con- 
sequently in  the  easier  and  greater  production  of  eggs,  fully 
account  for  the  gradual  passage  of  facultative  parasitism  into 
true  parasitism.  In  many  forms  the  young  stages  live  free  for 
some  time  (Strongyloides),  in  others,  as  is  the  case  in  Rhabdunema, 
parasitic  and  free-living  generations  alternate ;  in  others,  again, 
the  free  period  is  limited  to  the  egg  stage  or  entirely  suppressed. 

Though  it  is  possible  thus  to  connect  the  parasitic  with  the 
free-living  nematodes,  also  by  taking  their  manner  of  life  into 
account,  this  matter  presents  greater  difficulties  in  regard  to  other 
helminthes.  It  is  true  that  the  jointed  cestoda  may  be  connected 
with  and  traced  from  the  less  known  and  interesting  single- 
jointed  cestoda  (Amphilina,  Archigetes,  Caryophyll&us,  Gyrocotyle), 
but  trematodes  are  all  parasites,  with  the  exception  of  one  form, 
Temnocephala,  a  peculiarly  shaped  creature,  several  species  of  which 
live  on  the  surface  of  the  body  of  crustaceans  and  freshwater 
turtles.  Temnocephala  is,  nevertheless,  a  predacious  animal ;  it 
feeds  on  infusoria,  the  larvae  of  small  insects  and  crustaceans. 
So  far  as  is  known  it  does  not  nourish  itself  on  parts  of  its  host; 
it  belongs  to  the  group  of  commensals,  or  more  correctly,  to  that 
•of  the  SPACE  PARASITES,  which  simply  dwell  with  their  host  and 
do  not  even  take  a  portion  of  the  -  superfluity  of  his  food.  How- 
ever, space  parasitism  may  still  be  regarded  as  the  first  stage  of 
commensalism,  which  is  again  to  be  regarded  as  a  sort  of  transi- 
tion to  true  parasitism. 

It  is  possible  that  parasitism  came  about  in  this  way  in  the  trema- 
todes, in  which  connection  we  must  first  consider  the  turbellaria-like 
ancestors  of  the  trematodes.  Much  can  be  said  in  favour  of  such  a 
genetic  relationship  between  turbellaria  and  trematodes  and  hardly 
anything  against  it  ;  it  should  also  be  remembered  that  amongst 
discs  or  suctorial  pores,  and  which  are  only  differentiated  from 
the  few  .parasitic  turbellaria  there  are  some  that  possess  clinging 
ectoparasitic  trematodes  by  the  possession  of  a  ciliated  integu- 
ment, which  is  found  only  in  the  larval  stages  of  the  latter. 

The  ACANTHOCEPHALA  occupy  an  isolated  position.  Most  authors 
certainly  regard  them  as  related  to  the  nematodes  ;  in  any  case, 
however,  the  connection  is  not  a  close  one,  and  the  far-reaching 
alterations  which  must  have  occurred  prevent  a  clear  view.  Perhaps 
the  free  original  forms  of  acanthocephala  are  no  longer  in  existence, 
but  that  such  must  have  existed  is  a  foregone  conclusion. 

An  explanation  of  the  CHANGE  OF  HOST  so  frequent  in  parasites 
is  more  difficult  than  that  of  their  descent.  R.  Leuckart  is  of  I 


22  THE   ANIMAL   PARASITES    OF   MAN 

opinion  that  the  present  intermediary  hosts,  which  belong  princi- 
pally to  the  lower  animals,  were  the  original  hosts  of  the  parasites, 
and  fostered  both  their  larval  and  adult  stages.  It  was  only  in 
course  of  time  that  the  original  hosts  sank  to  the  position  of 
intermediary  hosts,  the  cause  for  this  alteration  being  that  the 
development  of  parasites,  especially  of  the  helminthes,  through 
further  development  and  differentiation  extended  over  a  larger 
number  of  stages.  The  earlier  stages  remained  in  their  original 
hosts,  but  the  later  stages  sought  out  other  hosts  (higher  animals). 
To  prove  this  Leuckart  points  out  that  the  mature  stages  of 
the  helminthes,  with  but  few  exceptions,  occur  only  in  the  verte- 
brates which  appeared  later  in  the  development  of  the  animal 
kingdom,  while  the  great  majority  of  intestinal  worms  of  the  lower 
animals  only  represent  young  stages,  which  require  transmission 
into  a  vertebrate  animal  before  they  can  become  mature.  The 
few  helminthes  that  attain  maturity  in  the  lower  animals  (Aspido- 
gaster,  Archigetes)  are  therefore  regarded  by  Leuckart  as  primitive 
forms,  and  he  compares  them  with  the  developmental  stages 
of  helminthes,  Aspidogaster  going  through  a  change  of  host  with 
Redia,  Archigetes  with  Cystercoidea.  He  classes  the  nematodes 
that  become  mature  in  the  invertebrates  with  Angui&ulida,  i.e.,  with 
saprophagous  nematodes  from  which  the  parasitic  species  descend. 

Leuckart  therefore  regards  the  change  of  host  as  secondary, 
so  does  Sabatier.  The  latter,  however,  adduces  other  reasons 
for  this  (lack  of  clinging  organs  and  the  necessity  to  develop 
them  in  an  intermediary  stage) ;  but  in  this  connection  he  only 
considers  the  Cestoda.  In  opposition  to  Leuckart,  R.  Moniez, 
however,  is  convinced  that  the  migrations  of  the  helminthes,  as 
well  as  the  system  of  intermediary  hosts,  represent  the  original 
order  of  things.  Moniez  traces  all  Entozoa  from  saprophytes,  but 
only  a  few  of  these  were  able  to  settle  directly  •  into  the  intestine 
and  there  continue  their  development.  These  are  forms  that  at 
the  present  day  still  lack  an  intermediary  host,  such  as  Tricho- 
cephalus,  Ascaris  and  Oxyuris.  In  most  other  cases  the  embryos, 
however,  consisted  of  such  saprophytes  as  were,  in  other  respects, 
suitable  to  become  parasites  but  were  incapable  of  resisting  the 
mechanical  and  chemical  influences  of  the  intestinal  contents  ', 
they  were  therefore  obliged  to  at  once  leave  the  intestine,  and 
accomplished  this  by  penetrating  the  intestinal  walls  and  burrow- 
ing in  the  tissues  of  their  carriers.  In  this  position,  assisted  by 
the  favourable  conditions  of  nutrition,  they  could  attain  a  rela- 
tively high  degree  of  development.  Mechanical  reasons  pre~ 


DERIVATION    OF   PARASITES  23 


vented  a  return  into  the  intestines,  where  the  eggs  could  be 
deposited.  Most  of  them  doubtless  died  off,  as  parasites  at 
present,  as  also  their  young  stages  do  when  they  penetrate  wrong 
hosts.  A  part  of  them,  nevertheless,  passively  reached  the  intes- 
tine of  beasts  of  prey.  Many  were  -destroyed  in  the  process  of 
mastication  ;  for  a  small  part,  however,  there  was  the  chance  of 
reaching  the  intestine  of  a  beast  of  prey  undamaged,  and  there, 
having  become  larger  and  more  capable  of  resistance,  maturity 
was  attained.  By  means  of  this  incidental  coincidence  of  various 
favourable  circumstances,  these  processes,  according  to  Moniez, 
have  been  established  by  heredity  and  have  become  normal. 

This  is  not  the  place  to  express  an  opinion  either  for  or 
against  the  various  hypotheses  advanced,  but  the  existence  of 
these  diametrically  opposed  views  will  alone  show  the  great  diffi- 
culty of  the  question.  Independently,  however,  it  appears  more 
natural  to  come  to  the  conclusion  that  parasitism  as  well  as 
change  of  hosts  were  gradual  transitions. 

As  a  conclusion  to  this  introductory  chapter,  I  append  a  list 
of  the  most  important  works  on  the  helminthology  of  man  and 
animals. 


LITERATURE. 

GOEZE,   J.  A.  E.     Versuch  einer   Naturgeschichte  der  Eingeweidewurmer  thierischer 

Korper.     Blankenburg,  1782.     4to,  471  pp.,  with  44  plates. 
ZEDER,  J.  G.  H.     Erster  Nachtrag  zur  Naturgeschichte  der  Eingeweidewurmer,  von 

J.  A.  E.  Goeze.     Leipzig,  1800.     4to,  with  6  tables. 
RUDOLPHI,   C.    A.     Entozoorum   sive   vermium  intestinalium   historia  naturalis.     I., 

Amstelod.,  1808  ;    ii.,  1809.     8vo,  with  18  plates. 

RUDOLPHI,  C.  A.     Entozoorum  synopsis.     Berol.,  1819.     8vo,  with  3  plates. 
BREMSER,  J.  G.     Ueber  lebende  Wiirmer  im  lebenden  Menschen.     Wien,  1819.     8vo, 

with  4  plates. 
BREMSER,  J.  G.     Icones  helminthum,  systema  Rudolphii  entozoologicum  illustrantes. 

Viennae,  1824.     Fol.  (Paris,  1837). 
DUJARDIN,  F.     Histoire  naturelle  des  helminthes  ou  vers  intestinaux.     Paris,   1845. 

8vo^  with  1 2  plates. 
DIESING,    C.    M.     Systema    helminthum.     2    vols.     Vindobonae,     1850,     1851.     8vo. 

Supplements  by  the  same  author  :    Revision  der  Myzhelminthen  (Report  of 

the  Session  of  the  Imp.  Acad.  of  Science.     Wien.,  xxxii.,  1858)  ;  with  addendum 

(ibid.,  xxxv.,  1859)  ;  Revision  der  Cephalocotyleen  (ibid.,  xlix.,  1864,  and  xlviii., 

1864);    Revision  der  Nematoden  (ibid.,  xlii.,  1861);    Supplements  (ibid.,  xliii., 

1862). 
BENEDEN,   P.   J.,  van.     Memoire  sur  les  Vers  intestinaux.     Paris,    1858.     4to,  with 

12  pi. 
KUCHENMEISTER,  F.    Die  in  urid  an  dem  Korper  des  lebenden  Menschen  vorkommenden 

Parasiten.     Leipzig,  1855.     8vo,  with  14  plates. 
LEUCKART,  R.     Die  menschlichen  Parasiten  und  die  von  ihnen  herruhrenden  Krank- 

heiten.     I.,  Leipzig,  1863  ;    II.,  Leipzig,   1876.     8vo. 
COBBOLD,  T.  Sp.    Entozoa ;  an  Introduction  to  the  Study  of  Helminthology.    London, 

1864.     8vo.     Supplement,  London,  1869. 
DAVAINE,  C.     Traite  des  entozoaires  et  des  maladies  vermineuses  de  l'homme  et  des 

animaux  domestiques.     2nd  edit.     Paris,  1877.     8vo. 


24  THE   ANIMAL   PARASITES   OF   MAN 

LINSTOW,  O.  v.  Compendium  der  Helminthologie,  ein  Verzeichniss  der  bekannten 
Helminthen,  die  frei  oder  in  thierischen  Korpern  leben,  geordnet  nach  ihren 
Wohnthieren,  unter  Angabe  der  Organe,  in  denen  sie  gefunden  sind,  und  mit 
Beifiigung  der  Litteraturquellen.  Hannov.,  1878.  8vo.  Supplement,  includ- 
ing the  years  1878-1888,  Hannov.,  1888. 

COBBOLD,  T.  Sp.  Parasites ;  a  Treatise  on  the  Entozoa  of  Man  and  Animals,  including 
some  Account  of  the  Entozoa.  London,  1879.  8vo. 

LEUCKART,  R.  Die  Parasiten  des  Men^chen  und  die  von  ihnen  herriihrenden  Krank- 
heiten.  2nd  edit.  Leipzig,  1879.  The  Protozoa,  Cestodes,  Trematodes  and 
Hirudinei  have  hitherto  appeared  (continued  by  Brandes). 

BUTSCHLI,  O.  Protozoa  in  Bronn's  Klass.  u.  Ordn.  d.  Thierreichs.  Vol.  i.,  Leipz.,  1880- 
1889.  8vo,  with  79  plates. 

BRAUN,  M.  Trematodes  in  Bronn's  Klass.  u.  Ordn.  d.  Thierreichs.  Vol.  iv.,  i,  Leipz., 
1879-1893.  8vo,  with  33  tables.  (The  first  thirteen  sheets,  comprising  the  his- 
tory of  the  worms  up  to  1830,  were  compiled  by  H.  Pagenstecher.) 

ZtiRN,  F.  A.  Die  thierischen  Parasiten  auf  und  in  dem  Korper  unserer  Haussauge- 
thiere,  sowie  die  durch  erstere  veranlassten  Krankheiten,  deren  Behandlung 
und  Verhutung.  2nd  edit.  Weimar,  1882.  8vo,  with  4  plates. 

COBBOLD,  T.  Sp.  Human  Parasites  ;  a  Manual  of  Reference  to  all  the  Known  Species 
of  Entozoa  and  Ectozoa.  London,  1882.  8vo. 

KUCHENMEISTER,  F.,  and  F.  A.  ZURN.  Die  Parasiten  des  Menschen.  2nd  edit. 
Leipzig,  1888.  8vo,  with  15  plates. 

BLANCHARD,  R.     Traite  de  zoologie  medicale.     I.,  Paris,  1889;    II.,  1890.     8vo. 

NEUMANN,  L.  G.  Traite  des  maladies  parasitaires  non  microbiennes  des  animaux 
domestiques.  2nd  edit.  Paris,  1892.  8vo. 

Looss,  A.     Schmarotzerthum  in  der  Thierwelt.     Leipzig,  1892.     8vo. 

RAILLIET,  A.     Traite  de  zoologie  medicale  et  agricole.     2nd  edit.     I.,  Paris,  1893.     8vo. 

PARONA,  C.     L'elmintologia  italiana  da'  suoi  primi  tempi  all'  anno,   1890.     Geneva, 

1 894.  8vo. 

BRAUN,  M.     Cestoda  in  Bronn's  Klass.  u.  Ordn.  d.  Thierreichs.     Vol.  iv.,  2,  Leipzig, 

1894-1900.     8vo,  with  24  plates. 
MOSLER,  F.,  und  E.  PEIPER.     Thier  Parasit.  (Spec.  Path.  u.  Ther.  v.  H.  Nothnagel. 

Vol.  vi.)     Wien,  1894.     8vo,  with  1 24  illustrations. 
LAVERAN  et  R.   BLANCHARD.     Les  hematozoaires  de  rhomme  et  des  anim.     Paris, 

1895.  i2mo,  with  30  figs. 

SLUITER,  C.  R.     De  dierl.  paras,  v.  d.  mensch  en  van  onze  huisdier.     Haag,  1895.     8vo- 
BLANCHARD,  R.     Malad.  parasit.,  paras,  animaux,  paras,  veget.  a  1'exclus.  des  bacter. 

(Traite  de  pathol.  gen.  de  Ch.  Bouchard  T.,  vol.  ii.)      Paris,  1895.      8vo,  with 

70  figs. 
HUBER,    J.  Ch.     Bibliographic  der   klin.  Helminthol.     Miinchen,  1895.     8vo-     With 

Suppl.,  1898,  and  continued  as  Bibl.  d.  klin.  Entomol.     Miinchen,  1899-1900. 
MONIEZ,  R.     Traite  de  parasitol.  anim.  et  veget.  appl.  a  la  medecine.     Paris,   1896. 

8vo,  with  116  figs. 
WEICHSELBAUM.     Parasitologie    (Weil's    Handb.   d.    Hyg.).     Jena,    1898.     8vo,    with 

78  illustrations. 
KRAEMER,  A.  .  Die  thierischen  Schmarotzer  des  Auges  (Grafe  and  Samisch's  Handb. 

d.  ges.  Augenheilk.).     Leipzig,  1899.     8vo,  with  1 6  illustrations. 
CHOLODKOWSKY,  N.  A.     Icones  helm,  hominis.     St.  Petersburg,  1898-99.     Fol.  (atlas, 

with  15  plates). 
Journals. — Besides    the   zoological    and    medical    journals,    the   following    are    of 

interest : — 
Centralblatt   filr    Bacteriologie    und  Parasitenkunde,    edited    by   Loeffler,    Pfeiffer   and 

Braun  ;  and 
Archives  de  Parasitologie,  edited  by  R.  Blanchard. 

The  following  book  is  of  importance  to  medical  men  : — 
OSTERTAG,    R.     Handbuch    der    Fleischbeschau.     4th   edit.     With   260   illustrations. 

Stuttgart,    1902. 


THE  ANIMAL  PARASITES  OF   MAN. 


MAN  is  one  of  those  organisms  in  which  a  whole  host  of  parasites 
find  conditions  suitable  for  their  existence  :  Protozoa,  Plathelminthes, 
Nematodes,  Acanthocephala,  Hirudinea,  and  a  large  number  of  Arthropoda, 
Arachnida,  as  well  as  Insects,  all  include  members  which  are  parasites  of  man. 
These  creatures  either  live  on  the  external  surface  of  the  body  or  within 
the  intestine  and  its  appendages  ;  yet  other  organs  and  systems  are  not 
quite  free  from  foreign  guests — we  are  acquainted  with  parasites  in  the 
bones,  in  the  circulatory  system,  in  the  brain,  in  the  muscles,  in  the  excre- 
tory and  genital  organs,  and  even  in  the  organs  of  sense. 

Although  it  is  possible  in  a  xway,  and  perhaps  might  be  advantageous, 
to  arrange  and  describe  the  parasites  of  man  according  to  the  situations 
in  which  they  are  found  (parasites  of  the  skin,  intestinal  parasites,  &c.),  their 
description  in  the  various  stages  of  development  would  doubtless  be  disturbed 
when,  as  is  generally  the  case,  the  different  stages  are  passed  in  different 
organs,  and  a  work  which  treats  more  fully  of  the  natural  history  of  the 
parasites  than  of  the  local  disorders  they  give  rise  to  would  suffer  thereby. 

I  therefore  prefer  to  describe  the  parasites  of  man  in  their  systematic 
order,  and  to  mention  their  different  anatomical  stations  in  man  in  describing 
each  species. 

A.     PROTOZOA   (Primitive  Creatures). 

All  those  animal  organisms  which  throughout  their  entire  life  never 
rise  above  the  unicellular  stage,  or  merely  form  simple,  loose  colonies 
of  similar  unicellular  creatures,  are  grouped  under  the  term  Protozoa,  as 
the  simplest  types  of  animal  life  All  the  vital  functions  of  these,  the  lowest 
forms  of  animals,  are  carried  out  by  their  bodily  substance,  the  SARCODE 
(protoplasm);  often  particular  parts  possess  particular  functions;  but  the 
limits  of  a  cell  are  never  over-stepped  thereby  ;  these  special  parts  of  the 
cells  are  called  "cell-organs"  ;  recently  they  have  been  termed  "organelles." 

The  living  protoplasm  has  the  appearance  of  a  finely  granular,  viscid 
substance  which,  as  a  rule,  when  not  surrounded  by  dense  investing  mem- 
branes or  skeletons,  exhibits  a  distinct  kind  of  movement,  which  has  been 
termed  AMOEBOID  ;  according  to  the  species,  processes  of  various  forms  and 
various  numbers  called  pseudopodia  are  projected  and  withdrawn,  and  with 
their  assistance  these  tiny  creatures  glide  along,  one  might  almost  say  flow 
along,  over  the  surface.  In  most  protozoa  two  layers  of  plasma  may  be 
recognised,  and  distinguished  by  their  appearance  and  structure,  namely, 


26  THE   ANIMAL   PARASITES    OF   MAN 

the  superficially  situated,  viscid,  and  quite  hyaline  ECTOSARC  or  ectoplasm, 
and  the  more  fluid  and  always  granular  ENDOSARC  (endoplasm)  which  is 
entirely  enveloped  by  the  ectoplasm.  The  two  layers  have  different  func- 
tions, the  movements  originate  from  the  ectosarc,  which  also  undoubtedly 
fulfils  the  functions  of  breathing,  introduction  of  food  and  excretion  ;  the 
endosarc,  which  in  some  forms  (Radiolaria]  is  separated  from  the  ectosarc 
by  a  membrane,  undertakes  the  digestion  of  the  food.  To  this  apportion- 
ment of  functions  to  various  layers  of  plasma  is  due  the  development  of  par- 
ticular cellular  organs,  such  as  the  appearance  of  CILIA  (filaments),  FLAGELLA 
(whips),  SUCTORIAL  TUBULES  (in  the  Suctoria}  and  the  myophanes,  contractile 
parts  of  the  ectosarc  in  infusoria  and  gregarines,  differentiated  by  striation 
In  many  cases  (Flagellata,  Ciliata),  a  place  is  formed  for  the  ingestion 
of  food  (oral  part,  cytostom)  to  which,  not  rarely,  there  is  added  a  straight 
or  curved  opening  (cytopharynx),  through  which  the  food  reaches  the 
endosarc  ;  the  indigestible  residue  is  either  cast  off  through  the  oral 
part  or  excreted  by  a  special  anal  part  (cytopyge).  In  rare  cases,  organs 
sensitive  to  light,  the  so-called  pigment  or  optic  spots  (Euglena),  are 
developed.  In  the  case  of  infusoria  the  endosarc  circulates  slowly,  and 
agglomerations  of  fluids  (FOOD  VACUOLES)  sometimes  appear  around  each 
bolus  of  food  ;  in  these  vacuoles  the  food  is  digested  under  the  action 
of  certain  materials  (ferments).  Even  in  the  lowest  protozoa  fluids  to  be 
excreted  are,  as  a  rule,  gathered  into  one,  or,  more  rarely,  several  "  CON- 
TRACTILE VACUOLES,"  which  regularly  discharge  their  contents  ;  this  action, 
however,  is  to  a  certain  extent  governed  by  the  temperature  of  the  sur- 
rounding medium.  In  some  infusoria  a  tube-like  gap  in  the  plasm  is 
joined  to  the  contractile  vacuole  which  usually  occupies  a  certain  position  ; 
this  forms  a  sort  of  excretory  duct,  and  there  are  also  supply-canals 
leading  to  these  cellular  organs. 

Very  frequently  various  substances  are  deposited  in  the  endosarc,  such 
as  fatty  granules,  drops  of  oil,  pigment  granules,  bubbles  of  gas  or  crystals. 
More  solid  skeletal  substances  are  secreted  in  or  on  the  ectosarc.  To  the 
latter  belong  the  cuticles  of  the  sporozoa  and  infusoria,  the  chalky  shells 
containing  one  or  several  chambers  of  the  Foraminifera,  the  siliceous  and 
very  ornamental  framework  of  the  Radiolaria,  and  the  chitinous  integument 
of  many  Flagellata,  Infusoria,  &c.  Some  forms,  such  as  the  Amoebinae, 
make  use  of  foreign  bodies  found  in  their  surroundings,  such  as  grains  of 
sand  and  so  on,  to  build  their  shelters. 

The  FOOD  consists  of  small  animal  or  vegetable  organisms  and  of  organic 
waste  ;  it  is  usually  introduced  in  toto  into  the  endosarc.  On  the  other  hand, 
the  suctoria  extract  the  substance  from  their  prey  by  means  of  their  suctorial 
tubes.  Many  parasitic  species  also  ingest  solid  food,  others  feed  themselves 
by  endosmosis. 

In  all  cases  ONE  NUCLEUS  at  least  is  present.  It  is  true  that  the  exist- 
ence of  non-nucleated  protozoa,  the  M  oner  a,  is  still  insisted  upon,  but  some 
of  these  have  already  proved  to  be  nucleated,  and  the  presence  of  nuclei 
in  the  others  will  no  doubt  be  established.  Very  often  the  number  of 
nuclei  increases  considerably,  but  these  multi-nucleated  stages  are  always 
preceded  by  mononucleated  stages.  In  the  infusoria,  in  addition  to  the 
larger  or  principal  nucleus  (macronucleus)  there  is  usually  a  smaller  acces- 
sory or  deputy  nucleus  (micronucleus). 


CLASSIFICATION    OF   THE    PROTOZOA  2/ 

The  form  and  structure  of  the  nucleus  vary  exceedingly  in  different 
species  ;  there  are  elongated,  kidney-shaped,  or  even  ramified  nuclei  as  well 
as  spherical  or  oval  ones  ;  in  addition  to  vesicular  -  shaped  nuclei  with  a 
distinct  nucleolus  and  incidentally  also  with  a  nuclear  framework,  we  also 
frequently  come  across  homogeneous  and  more  solid  formations.  The  nuclei 
are  always  differentiated  from  the  protoplasm  by  their  reactions,  particularly 
in  regard  to  certain  stains. 

The  nucleus  plays  the  same  part  in  the  life  of  the  single  celled  organ- 
isms as  it  does  in  the  cells  of  the  metazoa  and  metaphytes  ;  it  appears 
to  influence  in  a  certain  manner  all,  or  at  least  most  of,  the  processes  of  life, 
such  as  motility,  regeneration,  growth,  and  apparently  also  digestion ;  its 
principal  influence,  however,  is  exercised  in  the  propagation  of  the  cells,  as 
this  is  always  brought  about  by  the  nucleus. 

The  PROPAGATION  of  the  protozoa  is  effected  either  by  division  or  by 
means  of  direct  budding.  In  division,  which  is  preceded  by  direct  or 
indirect  (mitotic)  division  of  the  nucleus,  the  body  separates  into  two, 
several,  or  even  a  great  many  segments  ;  in  this  process  the  entire  sub- 
stance of  the  body  is  involved,  or  a  small  residual  fragment  may  be 
left  which  does  not  undergo  further  division  and  finally  perishes.  In  the 
budding  method  of  multiplication  a  large  number  of  buds  are  formed  either 
on  the  surface  or  in  the  interior  of  the  creature.  Where  divisions  or 
buddings  follow  one  another  rapidly,  without  the  segments  separating  imme- 
diately after  their  production,  numerous  forms  develop,  which  are  unlike  the 
parental  forms,  and  these  are  termed  swarming  spores  or  spores.  Divisions 
imperfectly  accomplished  lead  to  the  formation  of  protozoal  colonies. 

Sometimes  encystment'  takes  place  previous  to  division  ;  frequently,  also, 
sexual  processes  appear,  such  as  the  union  of  two  similar  (isogamia)  or 
dissimilar  (anisogamia)  individuals  ;  the  union  may  be  permanent  (copula- 
tion), the  process  being  comparable  to  the  fecundation  of  the  ovum  by 
a  spermatozoon,  or  the  union  may  be  transient  (conjugation) ;  after  the 
exchange  of  portions  of  the  nucleus  the  couple  separate,  to  multiply  indepen- 
dently of  each  other.  Sometimes  there  is  an  ALTERNATION  OF  GENERATION, 
through  there  being  several  methods  of  propagation  combined  in  the  same 
species,  either — conjugation  or  copulation — being  practised  ;  the  different 
generations  may  thus  differ  considerably  in  certain  cases. 

Protozoa  inhabit  salt  water  as  well  as  fresh  water  ;  they  are  also 
found  on  land  in  very  damp  places,  and  invade  animals  as  parasites. 


CLASSIFICATION  OF  THE  PROTOZOA. 

Class  I. — Rhizopoda  (Sarcodina).  Protozoa,  the  body  substance  of  which 
forms  pseudopodia ;  most  of  them  are  capable  of  developing  chitinous,  chalky, 
or  gravelly  coverings  or  frameworks,  which,  however,  permit  the  protrusion 
of  the  pseudopodia  either  over  the  entire  periphery  or  at  certain  points. 
They  possess  one  nucleus  or  several. 

1  Independently  of  propagation,  many  protozoa  protect  themselves  from  death 
by  encystment  when  the  water  in  which  they  are  living  dries  up  ;  in  this  condition 
the  wind  may  carry  them  over  wide  tracts  of  land. 


28  THE    ANIMAL    PARASITES    OF    MAN 

Order  i. — Amcebina  (Lobosa)  naked  or  with  a  simple  shell,  sometimes 
formed  of  a  foreign  substance ;  the  pseudopodia  may  be  lobu- 
lated  or  finger-shaped  ;  there  is  a  contractile  vacuole  ;  generally  only 
one  nucleus.  They  live  in  fresh  or  salt  water,  in  the  soil,  and 
also  parasitically. 

Order  2. — Foraminifera  (Reticularia).  Mostly  provided  with  a  chalky 
shell,  usually  consisting  of  several  chambers,  and  allowing  the  pro- 
trusion of  the  pseudopodia  either  at  the  periphery  or  only  at  the 
opening.  The  pseudopodia  are  filamentous  and  frequently  anasto- 
mosed ;  there  is  no  contractile  vacuole  ;  there  are  usually  several 
nuclei.  Marine. 

Order  3. — Heliozoa.    Naked,  with  a  chitinous  or  simple  radial  chalky  frame- 

'  work  ;    the  pseudopodia  are  filamentous,  and  are  frequently  supported 

by  firmer  axis  filaments,  which  exhibit   no   tendency  to  anastomosis  I 

there  is  a  contractile  vacuole  ;   one  or  several  nuclei.     Live  in  fresh 

water. 

Order  4. — Radiolaria.  The  body  has  raflially-placed  filamentous  pseudo- 
podia, and  the  nucleus  is  hidden  in  the  central  capsule  ;  there  is 
almost  always  a  silicious  framework,  consisting  of  pieces  arranged 
radially ,  tangentially,  or  lattice-like  ;  there  is  no  contractile 
vacuole  ;  but  there  are  always  vesicular  vacuoles  in  the  peripheral 
sarcode.  Marine. 

Class  II. — Flagellata  (Mastigophora).  Protozoa  with  one  or  several  long 
flagella  used  for  locomotion  and  for  acquiring  food ;  in  stationary  forms  their 
only  function  is  to  draw  in  food  ;  cytostom  common,  contractile  vacuole 
always  present.  May  be  either  naked  or  provided  with  shells  and  shelters  ; 
one  nucleus  only.  They  live  either  in  fresh  or  salt  water,  or  may  be  parasitic. 
This  class  is  again  divided  into  several  sub-classes  or  orders,  of  which  only 
the  Euflagellata,  with  the  Monadihes  and  Polymastigodes,  are  of  interest  here. 
Class  III. — Sporozoa.  Protozoa  that  only  live  parasitically  in  the  cells, 
tissues,  or  organs  of  other  animals  ;  they  ingest  liquid  food  by  osmosis  ; 
the  surface  of  the  body  is  covered  with  an  ectoplasmatic  layer,  or  cuticle  ; 
have  no  cilia  in  the  adult  state,  and  rarely  form  pseudopodia  ;  flagella 
occur,  but  only  on  the  male  propagating  individuals.  There  may  be  one 
or  numerous  nuclei,  but  no  contractile  vacuole.  Propagation  by  means  of 
spores,  mostly  provided  with  shells,  is  characteristic  ;  division  and  budding 
seldom  occur,  but  alternation  of  generations  is  frequent. 

Sup-class  T. — Telosporidia  (Cytosporidia)  are  usually  of  one  constant  form, 
rarely  amoeboid  ;  are  always  mononuclear  in  the  mature  state ; 
they  live  within  cells  in  the  first  stage.  Sporulation  at  the  end 
of  life. 

Order  i. — Gregarinida.  Body  of  a  constant,  usually  elongated  form, 
surrounded  by  a  cuticle.  In  the  early  stage  they  lead  an  intra- 
cellular  existence  ;  in  the  mature  stage  they  live  within  the  intestine 
or  abdomen  of  invertebrate  animals,  especially  the  arthropoda, 
and,  like  intestinal  parasites,  are  provided  with  clinging  organs. 
Fecundation  isogamic  ;  the  spores  have  shells,  no  polar  bodies, 
and  usually  contain  several  minute  germs  (sporozoites). 
Order  2. — Coccidiida  (Coccidiomorpha).  Body  of  uniform  spherical  or 
oval  shape  ;  intracellular  life,  but  are  not  freely  motile  in  cavi- 


RHIZOPODA  .    29 

ties  of  the  body.      Fecundation  anisogamous  ;  spores  have  shells 
without  polar  bodies,   mostly  with  several  sporozoites. 

Order  3. — Hcemosporidia.  Parasites  of  the  blood  corpuscles  of  verte- 
brate animals  ;  they  exhibit  amoeboid  movements  ;  present  alterna- 
tion of  generations  and  hosts  ;  spores  naked. 

Sub-class  2. — Neosporidia.  They  are  polynucleated  in  the  adult  state  ; 
the  form  of  the  body  varies  exceedingly  ;  sporulation  commences 
even  before  the  completion  of  growth.  . 

Order  i. — Myxosporidia.  The  spores  have  shells,  with  or  without  caudal 
appendages,  with  two,  rarety  four,  polar  capsules.  They  live  free 
in  such  organs  as  the  gall  or  urinary  bladder,  but  are  chiefly 
found  in  connective  tissue,  and  especially  in  fishes. 

Order  2. — Microsporidia.  Spores  with  shells  ;  no  caudal  appendage, 
with  one  polar  capsule.  They  usually  live  in  the  tissues  of  the 
arthropoda. 

Order  3. — Sarcosporidia.  Elongated  parasites  of  the  muscular  fibres  of 
amniotic  vertebrate  animals,  on  rare  occasions  they  occur  also 
in  the  connective  tissue  ;  the  spores  are  naked,  have  no  polar 
bodies  (?)  ;  kidney-  or  sickle-  shaped. 

Class  IV. — Infusoria  (Ciliata).  The  body  is  generally  uniform  in  shape, 
with  cilia,  contractile  vacuole,  frequently  also  with  cytostom  ;  usually  has 
macro-  and  micro-  nucleus  ;  live  free  in  water  and  also  parasitically. 

The  orders  Holotricha,  Heterotricha,  Hypotricha  and  Peritricha  are  classified 
according  to  the  arrangement  of  the  cilia. 

Class  V. — Suctoria  are  bodies  with  suctorial  tubes,  contractile  vacuoles, 
macro-  and  micro-  nucleus,  no  cytostom.  They  generally  invade  aquatic 
animals  as  space  parasites,  yet  also  attack  plants  ;  early  stage  ciliated.  Live 
frequently  as  parasites  in  infusoria. 

LITERATURE. 

Besides  the  zoological  works  (compare  Btitschli  and  A.  Lang)  and  those  already 

alluded  to,  the  following  may  be  noted  : — 

PFEIFFER,  L.  Die  Protoz.  als  Krankheitserreger.  2nd  edit.  Jena,  1891.  Supple- 
ments, Jena,  1895. 

SCHNEIDEMUHL,  G.  Die  Protoz.  als  Krankheitserreger  der  Menschen  u.  der  Haus- 
thiere.  Leipzig,  1898. 

DOFLEIN,  F.  Die  Protoz.  als  Parasiten  und  Krankheitserreger.  Jena,  1901  ;  and  the 
2nd  edit,  of  the  book. 


Class  I.     Rhizopoda. 

Order  i.     Amcebina. 
Gen.  i.     Amoeba,  Ehrbg. 

The  body  of  the  amoeba,  which  is  always  naked,  frequently  exhibits  the 
differentiation  of  the  ecto-  and  endo-  sarc  very  distinctly  ;  the  ectosarc  is 
viscid  and  hyaline,  the  endosarc  is  liquid  and  granular,  and  in  addition 
contains  food-particles  (free  in  the  plasma  or  enclosed  in  vacuoles),  fatty 
granules;  incidentally  also  crystals.  It  contains,  moreover,  the  compact 
or  vesicular  nucleus,  which  occurs  singly  in  nearly  all  species,  and  the  con- 
tractile vacuole  which  discharges  its  watery  contents  with  acid  reaction  to 


30   .  THE   ANIMAL   PARASITES    OF    MAN 

the  exterior,  and  in  some  species  into  the  surrounding  plasma.  Movements 
are  effected  by  means  of  pseudopodia,  processes  of  the  protoplasm  which 
may  be  projected  and  retracted  from  any  part  of  the  body.  Notwith- 
standing the  fact  that  this  causes  a  continuous  change  of  shape,  the  form, 
number  and  arrangement  of  the  finger-like  or  lobulate  pseudopodia  are 
characteristic  of  each  species,  and  together  with  the  size,  which  fluctuates 
between  croi  and  0-5  mm.,  and  the  structure,  as  well  as  the  number  of 
nuclei  and  the  constitution  of  the  protoplasm,  serve  to  distinguish  the 
species.  The  food,  consisting  of  the  tiniest  organisms  (bacteria,  algae, 
protozoa)  or  residues',  is  ingested  by,  the  body,  with  the  assistance  of  the 
pseudopodia,  i.e.,  is  ingulfed  by  the  protoplasm. 

Propagation  takes  place  by  means  of  segmentation,  after  previous  direct 
or  mitotic  division  of  the  nucleus.  After  the  completion  of  encystment 
and  after  the  successive  segmentation  of  the  nucleus  into  many  parts,  there 
occurs  a  division  into  numerous  segments,  each  containing  a  nucleus.  The 
division  either  involves  the  entire  plasm  or  leaves  a  residual  body. 
After  leaving  the  cell-membrane  the  segments  assume  an  amoeboid  or 
flagellated  form,  and  in  this  condition  they  are  capable  of  propagation 
through  longitudinal  division.  Finally,  they  give  up  flagellate  movement, 
sink  to  the  bottom,  and  continue  to  move  by  the  means  of  pseudopodia. 

The  amoebae  live  chiefly  in  stagnant  fresh  water,  creeping  about  at  the 
bottom  of  puddles  or  on  plants  ;  a  few  species  are  marine,  others  live  in 
moist  soil,  and  a  number  are  parasitic.  In  no  case  has  there  been  satis- 
factory evidence  to  prove  whether  the  amoebae  are  facultative  or  true 
parasites.  • 

All  the  amoeba-like  beings  one  comes  across  in  the  open,  or  in  infusions 
or  cultures,  are  not  independent  organisms,  but  developmental  forms  of 
other  animal,  or  particularly  vegetable,  organisms ;  this,  perhaps,  is  also  the 
case  in  some  of  the  parasitic  forms  :  the  task  of  distinguishing  the  latter 
from  body  cells  is  very  often  difficult.1 

i.     Amoeba  coli,  Loesch,  1875. 

Form,  roundish  or  pear-shaped  ;  size  fluctuates  between  0*008 
and  0-05  mm.  The  ectosarc  can  hardly  be  recognised  in  the 
quiescent  creature,  but  is  distinctly  visible  in  the  pseudopodia ; 
lhe  endosarc  is  more  or  less  finely  granular,  and  usually  contains 
white  and  red  blood  corpuscles  taken  up  for  food ;  it  may  also 
contain  eosinophile  cells,  bacteria,  epithelial  cells  and  particles  of 
faecal  matter ;  the  pseudopodia  are  broad,  lobose,  one  or  two 
being  protruded  at  a  time.  The  activity  of  the  movement 
depends  on  the  temperature  and  on  the  constituents  of  the 
surrounding  medium  :  when  the  contents  of  the  intestine  have  an 

1  The  literature  on  this  subject  is  found  in  Biitschli,  I.e.  in  R.  Behla,  Die  Amceben 
vom  paras,  und  culturell  Standpunkt  (Berlin,  1898,  8vo,  with  one  plate) ;  also  in  A.  Lang, 
Lehrb.  der  vergl.  Anat.  der  wirbellosen  Thieve,  2nd  edit.  (Jena,  1901,  8vo,  with  259 
illustrations)  Compare  also  Feinberg,  "  Ueber  Amosben  u.  ihre  Unterscheidung  von 
Korperzellen  (Fortschritte  der  Medic.,  1899,  xvii.,  p.  121). 


AMCEBA   COLI  31 

acid  reaction  the  intestinal  amoebae  die  off  ;  a  low  temperature 
retards  the  amoeboid  movement,  and  finally  causes  it  to  cease. 
The  number  of  vacuoles  varies ;  they  rarely  change  form.  A 
nucleus  is  always  present,  though  it  cannot  always  be  seen  in  the 
living  animal ;  after  death,  or  through  the  addition  of  reagents 
(acetic  acid,  sublimate),  it  shows  clearly ;  its  form  is  spherical, 


FIG.   i. — Amoeba  coli,  Loesch,  in  the  intestinal   mucus,  containing  blood  and  pus 
corpuscles.     (After  Loesch.) 

and  it  is  of  the  same  size  as  the  vacuoles  (0-006  mm.). 
According  to  some  authors  the  nucleolus  is  easily  detected,  others 
state  that  it  is  only  exceptionally  visible. 

The  propagation  of  the  amoeba  takes  place  in  the  intestine  by 
simple  division  (it  has  been  observed  by  Casagrandi  and  Barbagallo1 
as  well  as  by  Harris2).  The  transmission  to  other  hosts  is  appar- 


FIG.  2. — Encysted  intestinal  amceba  in  the  act  of  propagation.     (After  B.  Grassi.) 

ently  effected  exclusively  by  encysted  forms,  the  protoplasm  of 
which,  after  repeated  division  of  the  nucleus,  separates  itself 
into  as  many  parts  as  there  are  new  nuclei  (Casagrandi  and 
Barbagallo),  by  arranging  itself  round  each  new  nucleus.  According 


'Casagrandi,  O.,  and  Barbagallo,  P.,  "  SulV  amoeba  coli"  (Boll.  Accad.  Gioenea, 
sc.  nat.  Catania,  1895). 

a  Harris,  H.  F.,  "Some  Observations  on  a  Method  of  Multiplication  of  the  Amceba 
dysenteries"  (Med.  News,  1894,  Ixv.,  No.  21,  p.  567). 


32  THE    ANIMAL    PARASITES    OF   MAN 

to  Grassi,1  the  propagation  is  effected  by  amoebae,  the  protoplasm 
of  which  is  still  entire,  but  which  probably  will  divide  later. 
Calandruccio2  succeeded  in  infecting  himself  by  swallowing  encysted 
intestinal  amoebae ;  twelve  days  after  ingestion  amoebae  appeared  in 
his  faeces.  Quincke  and  Roos  obtained  the  same  result  in  experi- 
ments on  cats,  whereas  the  transmission  by  means  of  non-encysted 
amoebae  proved  negative. 

Amoebae  have  frequently  been  seen  in  the  fasces  evacuated  by  healthy 
persons  and  in  those  of  patients  suffering  from  the  most  varied  intestinal 
disorders.  They  were  first  discovered  by  LambP  at  Prague  in  1859,  in 
the  evacuations  of  a  child  suffering  from  dysentery,  but  this  discovery  was 
of  little  value  in  itself,  as  the  author  stated  that  he  had  also  found  Dimugia 
and  Arcella.  At  a  later  date  Lewis'  and  Cunningham5  observed  amoeboid 
organisms  in  the  stools  of  patients  suffering  from  cholera  and  other  diseases. 
We  owe  the  first  detailed  description  and  the  determination  of  the  species  to 
Losch,  who  found  amoebae  in  great  numbers,  as  well  as  pus  and  blood 
corpuscles,  in  the  stools  of  a  patient  in  St.  Petersburg  who  exhibited 
dysenteric  symptoms  (fig.  i).  Losch  was  also  the  first  observer  who 
sought  to  confirm  the  pathogenic  action  of  intestinal  amoebae  by  means 
of  experiment.  He  introduced  small  quantities  of  faeces  containing  amoebae 
into  four  dogs  per  os  et  anum,.  and  eighteen  days  later,  at  the  autopsy  of 
one  of  the  animals  that  had  already  passed  sanguineous  masses  of  mucus 
with  amoebae  soon  after  the  experiment,  he  found  several  ulcers  in  the 
rectum  containing  numerous  amoebae.  As  the  three  other  dogs  remained 
healthy,  Losch  expressed  the  opinion  that  the  amoebae  should  not  be 
regarded  as  a  cause  of  disease,  but  that  probably  they  prevented  the 
healing  of  intestinal  ulcers  previously  present,  thus  increasing  the  original 
inflammatory  conditions. 

The  occurrence  of  intestinal  amoebae  in  man  has  been  reported  from  a 
great  many  regions.  We  hear  of  them  in  Germany  (Pfeiffer,  Schuberg, 
Behla,  Quincke  and  Roos,  Roemer,  Boas,  Jaeger),  in  Austria  (Cahen,  Epstein, 
Manner,  Hlava,  Sorgo),  in  Russia  (Losch,  Massiutin,  Ucke),  in  Roumania 
(Babes  and  Zigura),  in  Bosnia  (Schardinger),  in  Greece  (Kartulis),  in  Italy 
(Grassi,  Calandruccio,  Fenoglio,  Casagrandi  and  Barbagallo,  Vivaldi),  in 
France  (Peyrot  and  Roger),  in  Algeria  (Gasser),  in  Egypt  (Sonsino,  Kartulis, 
Koch,  Kruse  and  Pasquale),  in  Abyssinia  (Grassi),  in  India  (Lewis,  Cunning- 
ham, Harold,  Manson,  Ross),  in  Hong  Kong  (Normand),  in  Tonquin 
(Laveran),  in  the  Philippines  (Flexner),  in  Sumatra  (Kovacs),  in  Saghalian 


1  Grassi,  B.,  "  Protoz.  paras,  e  spec,  quelli  che  sono  nelV  uomo  "    (Gazz.   med.    ital.- 
lomb,   1879,  No.  45);    "  Int.  ad  ale.  prot.  endop."  (Atti  soc.  ital.  sc.  nat.,  1882,  xxiv., 
p.  i)  ;    "  Morf.  e  sist.  di  ale.  prot.  par."  (Atti  Ace.  Lincei  Rend,  iv.,  i,  p.  5)  ;  "  Signif. 
patol.  d.  prot.  par.  dell'  uomo  "  (ibid.,  p.  83). 

2  Calandruccio,  "  Anim.  par,  dell'  uomo  in  Sicilia  "  (Att.  Ace.  Gioen.,  1890,  ii.,  p.  95). 

3  Lambl,  A.  d.  Franz-  Josephs-Kinder  spit.  i.  Prag.,  1860,  i.,  p.  362. 

4  Lewis,  Sixth  Ann.  Rep.  San.  Comm.  Government  of  India,  Calcutta,  1870. 

5  Cunningham,  D.,  Seventh  Ann.  Rep.  San.  Comm.  Gov.  of  India,  Calcutta,  1870. 

8  Losch,    F.,  "  Massenh.  Entw.  v.  Amceb.  i.  Dickdarm"  (Virchow's  Arch.  f.  Path., 
1875,  Ixv.,  p.  196). 


AMCEBA   COLI 


33 


(Lobas),  in  North  and  South  America  (Musser,  Stengel,  Councilman,  Howard, 
Osier,  Dock,  Lutz,  Fajardo,  Roemer). 

The  interest  aroused  in  the  intestinal  amoebae  of  man  is  to  be  ascribed  not 
so  much  to  their  world-wide  distribution  as  to  the  fact  that  they  are  supposed  to 
be  connected  with  a  serious  disease  to  which  man  is  subject,  namely,  dysentery. 
The  Commission  despatched  to  Egypt  and  India  in  1883  to  investigate  cholera  ' 
not  only  succeeded  in  discovering  the  bacillus  of  cholera,  but  also  col- 
lected information  regarding  dysentery.  In  Egypt,  Koch  performed  autopsies 
on  five  fatal  cases  of  dysentery.  In  four  of  these,  in  addition  to  bacteria, 
he  found  amoebae  at  the  bottom  of  the  ulcers  (on  sections)  ;  in  the  fifth 
case  the  ulcers  in  the  large  intestine  were  nearly  or  entirely  cicatrised. 
During  the  life  of  these  patients  amoebae  could  not  be  found  in  the  stools. 
The  same  author  made  similar  observations  in  India.  At  about  the  same 
time  Kartulis,  in  Alexandria,  discovered  amoeba-like  bodies  in  the  stools 
of  six  persons  suffering  from  chronic  inflammation  of  the  bowels,  or  diar- 
rhoea, and  he  described  these  as  "  giant 
amoebae."-'  Encouraged  by  Koch's  researches, 
Kartulis'  continued  his  studies  on  dysentery, 
and  was  able  to  confirm  the  presence  of 
amoebae  in  every  case  of  undoubted  dysentery 
(more  than  150  cases),  whereas  they  were 
entirely  absent  in  other  bowel  complaints  ;  he 
also  succeeded  in  demonstrating  amoebae  in 
sections  from  the  large  intestine,  but  only 
in  cases  of  dysentery,  and  not  in  other 
intestinal  diseases  involving  ulceration  of  the 
bowel.  Further  researches  on  over  500  cases 
confirmed  the  previous  observations.  Living 
amoebae  were  likewise  found  in  the  pus  of 
liver  abscesses,  which  frequently  follow  tropical 
dysentery,  the  parasites  presumably  passing 
from  the  intestine  to  the  liver  by  way  of 
the  blood-vessels.  R.  Koch's  (I.e.}  researches 


FIG.  3. — Amoeba  coli,  Losch, 
in  the  mucus  of  a  dysenteric 
stool,  with  red  blood  corpuscles. 
(After  Kovacs.) 


would  lead  one  to  form  the  same  conclusion.  Finally,  Kartulis4  was  able  to 
confirm  by  experiments  similar  to  those  of  Losch,  which  were  so  widely  dis- 
puted, that  animals,  especially  cats,  injected  with  dysenteric  faeces  or  pus  con- 
taining amoebae  easily  developed  a  disease  resembling  endemic  dysentery. 
In  reply  to  the  objection  raised,  that  in  such  experiments  impure  material 
was  used,  and  that  the  disease  in  the  animals  experimented  upon  was  due  to 
other  agents  (bacteria,  &c.),  Kartulis  communicated  a  successful  experiment 
in  which  the  infection  had  been  conveyed  by  pus  free  of  bacteria,  but 
containing  amoebae. 


1  Koch,  R.,  and  G.  Gaffky,  "  Ber  it.  d.  Th.it.  d.  z.  Erforsch.  d.  Cholerabac.  ents. 
Commits."  (Arb.  a.  d.  Kais.  Gesundheitsamte,  1887,  iii.,  Berl.,  1887). 

-  Kartulis,  "  Ueber  Riesenamceben  (?)  bei  chron.  Darmentz.  d.  Aegypt."  (Virchow's 
Arch.,  1885,  xcix.,  p.  145). 

3  Kartulis,  "  Z.  Mtiol.  d.  Dysent."  (ibid.,  1886,  cv.)  ;  "  Z.  Mtiol.  d.  Dys.  i.  Aeg." 
(C.  /.  B.  u.  P.  1887,  V.,  p.  745)  ;  "  Ueb.  trop.  Leberabs.  u.  ihr  Verh.  z.  Dys/'  (Virchow's 
Arch.,  1889,  cxviii.,  p.  97)  ;  "  Einiges  Hb.  d.  Pathog.  d.  Dysentene-Amceb."  (Centralbl. 
f.  B.  u.  P.,  1891,  ix.,  p.  365). 

'  Kartulis,  "Dysenteric  "  (Spec.  Path,  und  Ther.  von  H.  Nothnagel,  v.,  3,  Wien,  1806). 

3 


34  THE   ANIMAL    PARASITES    OF    MAN 

Kar  tulis'  views,  which  are  briefly  stated  here,  are  also  considered  by 
the  author  to  hold  good  for  endemic  (tropical)  dysentery.  They  have  met 
partly  with  assent,  and  partly  with  vehement  opposition.  The  authors 
who  support  Kartulis,  such  as  Councilman  and  Lafleur,1  Quincke  and  Roos/ 
Kruse  and  Pasquale,'  Kovacs,1  and  others,5  for  the  most  part  agree  on  the 
grounds  of  their  own  very  extensive  researches,  but  also  on  account  of  the 
irrefutable  arguments  adduced  by  Kartulis,  and  they  are  more  or  less  convinced 
of  the  pathogenic  action  of  Amoeba  dysenterica,  and  agree  in  regarding  the 
parasite  as  the  sole,  or  at  least  the  primary,  agent  in  the  causation  of 
endemic  (tropical)  or  amoebic  dysentery  or  amoebic  enteritis.  They  are 
also  of  opinion  that  the  bacteria  which  always  accompany  the  amceba  are 
not  specific,  but  possess  pathogenic  qualities  and  play  a  part  in  the  morbid 
process  induced  by  the  amoeba. 

The  opponents  base  their  opinion  on  the  fact  that  in  various  places 
intestinal  amoebae  are  either  invariably  absent  in  cases  of  true  endemic 
dysentery,  or  are  very  scarce,  as,  for  instance,  in  Japan,  Algeria,  the  Philip- 
pines ;  moreover,  that  they  are  found  in  the  evacuations  in  other  infectious 
and  non-infectious  intestinal  diseases  (typhus,  cholera,  colitis,  proctitis, 
acute  and  chronic  intestinal  catarrh,  &c.),  and  that  they  are  even  present 
in  perfectly  healthy  persons. t;  The  experimental  infection  produced  in 
animals  to  prove  the  pathogenic  nature  of  the  Amoebae  of  the  intestine 
is  not  considered  above  reproach.  Apart  from  the  circumstance  that 
all  the  experiments  were  not  followed  by  positive  results,  in  one  case, 
undoubtedly,  impure  material  was  used  ;  and  in  those  cases  where  test 
cultures  proved  that  the  material  was  free  from  bacteria,  no  absolute  proof 
of  this  condition  was  given.  Moreover,  it  is  also  possible  to  cause  a 
dysenteric  disease  in  mammals  (cats  were  mostly  used)  when  the  amoebae 
in  the  evacuations  used  for  injection  have  been  killed  off  by  the  addition 
of  water  or  by  heating,  or  even  when  ordinary  garden  mould  diluted 
with  water  is  used  for  the  injection.7  It  is  also  emphasised  that  the 
order  of  the  experiments  is  entirely  reversed,  because  the  infection  of  man 


1  Councilman,  W.  P.,  and  H.  A.  Lafleur,  "Amoebic  Dysentery"  (Johns  Hopk.  Hos. 
Rep.,  1891,  ii.,  p.  395)- 

-Quincke  and  Roos,  "  Ueb  A  mceb. -Enteritis"  (Berl.  klin.  Wchschrift.,  1893,  xxx., 
No.  45,  p.  1089);  Roos,  E.  Z.,  Kenntniss  der  Amcebenenteritis  (Arch.  filr  exp.  Path, 
und  Pharm.,  1894,  xxxiii.,  p.  389). 

3  Kruse,   W.,    and    Pasquale,    "  Eine  Exped.   n.   Mgypt."    (Dtsch.   med.    Wchschrft., 
1893,  No.   15,  p.' 354  ;    No.  16,  p.  378);    "  Unters.  ub.  Dys.  u.  Leberabsc."    (Ztschr.  /. 
Hyg.,  1894,  xvi.,  p.  i). 

4  Kovacs,  F.,  "  Beob.  u.  Vers.  Ub.  d.  so°.  Amceben-Dys."  (Zeitschr.  f.  Heilkde.,  1892, 
xiii.,  p.  5°9)- 

•'Compare  also  the  following  literature:  Schuberg,  A.,  "Die  para*.  A  mceb  en  d. 
tnenschl.  Darms  (C.  f.  B.,  u.  P.,  1893,  xiii.,  pp.  598,  654,  701)  ;  Janowski,  W.,  "  Z.  Aetiol. 
d.  Dys."  (C.  f.  B.,  P.  u.  /.,  1897,  xxi.,  pp.  88,  151,  194,  234). 

6  Schuberg,  A.  (C.  /.  B.  und  P.,  1893,  xiii.,  p.  598);  Casagrandi,  O.  G.  V.,  and 
P.  Barbagallo  (Boll.  Accad.  Gioenea  sc.  nat.  Catania,  1885)  »  Celli,  A.,  and  R.  Fiocca, 
"  Ueb.  d.  Aetiol.  d.  Dys."  (C.  f.  B.  u.  P.,  1895,  xvii.,  p.  309)  ;  Grassi,  B.  (Lc.)  ;  Massiutin, 
"  Amceb.  als  Paras,  d.  Dickdarms  "  (Wraisch,  1889,  No-  25>  Ref.  in  C.  f.  B.  u.  P.,  1889, 
vi.,  p.  451);  Laveran,  "  Etiol.  de  la  dys."  (Sem.  m'd.,  1893,  p.  508;  C.  R.  soc.  biol., 
1893,  v.,  p.  875). 

'  Gasser,  I.,  "  Notf  sur  la  cause  de  la  dys."  (Arch.  mcd.  exp.  et  d'anat.  pathol.,  1895, 
p.  198). 


AMOEBA   COLI  35 

certainly  does  not  take  place  per  anum.'  Moreover,  some  authors-  who 
have  received  intestinal  amoebae  from  various  sources  state  that  there  is 
no  morphological  difference  between  the  amoebae  of  tropical  and  European 
dysentery  ;  and  that  a  bacterium  of  which  there  are  apparently  several 
varieties  is  the  cause  of  dysentery  in  the  temperate  as  well  as  in  the 
tropical  and  subtropical  zone.1  The  specific  nature  of  these  bacteria  is 
proved  above  all  by  the  agglutination  which  the  blood  serum  effects  on  the 

bacteria  in  persons  ill  with  or  recovered  from 
the  infection,  the  serum  of  healthy  persons 
not  causing  agglutination.  Those  forms  of 
dysentery  caused  by  bacteria  and  in  which 
amoebae  are  either  not  found  or  very  rarely, 
are  excluded  from  the  discussion,  and  further 

, .  t        J.-U  proofs     will    be     necessary    in    order    to    gain 
FIG.  4. — Amceba  coll  from  the 

section  of  the  intestine  of  a  cat  general     recognition     for    the    etiology   of    the 

which  had  been  infected  with  so-called  amcebic    enteritis    or   amoebic   dysen- 

the  intestinal  amoeba  of  a  man.  t  It  t     however,   be  mentioned   that 

Stained     with    alum  -  carmine. 

(After  Kovacs.)  Kartulis  endeavoured   to   test   the   methods  of 

Celli  and  Fiocca  (killing  the  amoebae  by  warm- 
ing) and  of  Casagrandi  and  Barbagallo  (killing  the  amoeba  with  distilled 
water),  but  was  unable  to  confirm  their  results.  Kartulis,  by  means  of  test 
cultures  on  various  media,  assured  himself  of  the  absolute  purity  of  the 
abscess-pus  containing  amoebae  which  he  used  for  his  experiments. 

A  few  authors  take  up  an  intermediate  position,  in  so  far  as  they  admit 
of  the  existence  of  various  species  of  parasitic  amoebae  in  man.  One  of 
these  they  consider  innocuous,  because  it  is  found  more  or  less  frequently  in 
healthy  persons,  and  comes  under  observation  in  very  different  intestinal 
disorders,  while  another  they  believe  to  be  the  cause  of  amcebic  enteritis. 
Councilman  and  Lafleur  do  not  agree  with  this  view4  ;  they  designate 
the  amoeba  of  dysentery  plainly  as  Amoeba  dysenteries.  Kruse  and  Pasquale 
use  the  same  designation,  and  reserve  the  old  term,  Amceba  coli,  Losch,  for 
the  non-infectious  species.  Quincke  and  Roos  distinguish  three  species  : 


1  Janowski,  I.e.,  &c.,  and  others. 

2  Roemer,  F.,  "  Amoeb.  bei  Dys.    u.  Enteritis"    (Miinch.  med.   Wchschr,  1898,  xlv.. 
No.  2,  p.  41). 

1  Celli,  A.,  and  R.  Fiocca,  I.e.  ;  Laveran,  I.e.  ;  Zancarol,  "  Pathog.-  d.  abces  du 
foie  "  (Rev.  d.  chirurg.,  1893,  xiii.,  p.  671  ;  Ref.  in  C.  f.  B.  u.  P.,  1893,  xiv->  P-  638) ; 
Arnaud.,  '-'  Reck,  sur  I'ttiol.  de  la  dys,  ai'gue.  d.  pays  chaud  "  (Ann.  Inst.  Pasteur.,  1894, 
viii.);  Silvestri,  E.,  de  "  Contrib.  allo  stud,  del  I'etiol.  d.  dissent.,''  Torino,  1895  .'  Celli, 
A.,  "  Eziol.  d.  diss."  (Ann.  d'igien:  sperim,  1896,  vi.,  p.  204)  ;  Shiga,  K.,  "  Ueb.  d.  Dysen- 
terie  bacillus  "  (C.  /.  B.,  P.  u.  I.,  1898,  xxiv.,  pp.  817,  870,  912) ;  Celli,  A,,  and  G.  Valenti, 
"  Nochm.  iib.  d.  Aet.  d.  Dys."  (C.  /.  B.,  P.  u.  I.,  1899,  xxv.,  p.  481);  Escherich,  Z., 
"  Aet.  d.  Dys"  (ibid.,  1899,  xxvi.,  p.  385) ;  Flexner,  G.,  "  The  Etiology  of  Tropical  Dys 
entery  "  (ibid.,  1900,  xxviii.,  p.  62^)  ;  Kruse,  W.,  "  Ueb.  d.  Ruhr,  also  Volkskrkht.  u. 
ihr  Erreger  "  (Dtsch.  med.  Wchschr.,  1900,  xxvi.,  p.  637)  ;  "  Weit.  Unters.  ub.  d.  Ruhr 
u.  d.  Ruhrbacillen  "  (ibid.,  1901,  xxvii.,  pp.  370,  386)  ;  Volagussa,  F.,  "  Aetiol.  u.  Serum 
ther.  der  Kinderdys  "  (Ann.  d'igien.  sper.,  1901,  x.)  ;  Centralbl.  fiir  B.,  P.  und  /.,  1901, 
xxix.,  p.  639);  Lavkowiz,  X.,  "  Enierococc.  als  Ruhrerre^."  (ibid.,  p.  635). 

1  The  reason  that  Raph.  Blanchard,  who  in  1885  had  already  mentioned  the  amoeba 
of  dysentery  as  a  special  species  ("  Amoeba  intestinalis ,"  in  Traite  de  Zool.  mSd.,  vol.  i., 
Paris,  1885,  p.  15),  is  not  included  here,  is  that  the  author  himself  changed  his  views, 
and  only  recognises  one  species  of  amoeba,  the  A  mceba  coli,  in  the  intestine  of  man  (Mai. 
paras.,  &>c-.,  1895,  p.  658). 


36  THE   ANIMAL   PARASITES    OF    MAN 

a  small  species  (0-025  mm.),  finely  granular,  the  Amoeba  coli,  Losch,  which 
is  pathogenetic  to  man  and  the  cat  ;  a  larger  one  (0*040  mm.),  coarsely 
granular,  the  Amoeba  coli  mitis,  which  is  pathogenetic  to  man  but  not 
to  the  cat  ;  and  a  species  of  similar  appearance,  the  Amoeba  intestini 
vulgaris,  which  is  innocuous  both  to  man  and  cat.  Celli  and  Fiocca1  even 
go  a  step  further,  differentiating,  as  they  do,  the  following  species  in  the 
intestine  of  man  :  (i)  Amoeba  lobosa,  with  var.  guttula  (i.e.,  Amoeba  guttula, 
Duj.),  var.  oblonga  (i.e.,  A.  oblonga,  Schm.),  and  var.  coli  (i.e.,  A.  coli, 
Losch);  (2)  Amoeba  spinosa,  n.  sp.  (in  the  vagina  as  well  as  in  the  intestine 
of  persons  suffering  from  diarrhoea  and  dysentery) ;  (3)  Amoeba  diaphana, 
n.  sp.  (in  the  human  intestine  in  cases  of  dysentery)  ;  (4)  Amoeba  vermi- 
cularis,  Weisse  (in  the  vagina  and  in  the  intestine  in  dysentery)  ;  and  (5) 
Amoeba  reticularis,  n.  sp.  (in  the  intestine  in  dysentery).  These  authors  state 
that  they  have  also  found  all  these  species  free  in  the  soil  or  in  the 
ooze  of  waters,  and  have  cultivated  them  in  pure  cultures.  It  is,  however, 
probable  that  in  all  these  experiments  it  was  not  a  question  of  exclusively 
animal  organisms,  as  the  existence  of  the  latter  depends  on  food  very 
different  to  that  which  was  used  in  the  pure  cultures"  ;  it  is  therefore 
advisable  to  take  up  an  expectant  standpoint  in  this  connection. 

Of  the  species  differentiated  by  Quincke  and  Roos,  two  (A.  intestini 
vulgaris  and  A.  coli  mitis)  may  be  regarded  as  identical,  because  no  morpho- 
logical differences  have  been  described,  and  because  the  statement  that 
their  effect  on  man  is  different  is,  to  say  the  least,  doubtful.5  It  is  there- 
fore reasonable  to  infer  that  two  species  were  under  discussion,  one  patho- 
genic and  the  other  harmless.  The  possibility  of  a  morphological  difference 
between  the  two  forms  has,  however,  not  hitherto  been  proved,  and  has 
recently  been  again  denied,  notably  by  Roemer  (1898).  In  spite  of  the 
numerous  works  published  within  recent  years  on  the  intestinal  amoebae  of 
man,  no  definite  conclusion  has  yet  been  arrived  at.  Notwithstanding  this, 
at  the  present  time  medical  men  strictly  differentiate  bacillary  dysentery  from 
amoebic  dysentery  or  amoebic  enteritis  ;  the  former  occurs  in  Germany  in 
the  dysentery  district  (Kruse,  1900,  1901),  the  latter  particularly  in  East 
Prussia  (Jaeger,4  1902). 


1  Celli,  A.,  and  R.  Fiocca,  "  Beitr.  z.  Amcebenforsch,  II."  (C.   /.  B.  u.  P.,  1894,  xvi., 
p.   329);    "  Ric.  int.  alia  biol.  d.  Amcebe  "    (Bull.  Accad.  med.  Roma,   1894-95,  xxi.. 
p.  285)  ;   Ref.  in  C.  f.  B.,  P.  u.  I.,  1897,  xxi.,  p.  290. 

2  It  is  quite  different  with  the  experiments  of   Frosch  (C.  /.  B.,  P.  u.  /.,  1897,  P- 
926)  ;    Tsujitani  (ibid.,  xxiv.,  p.  666);    and  Schardinger  (Stzgsb.  d.  K.  Acad.  d.  Wiss. 
Wien.  Math.-mt.  Cl.,  1899,  cviii.,  part  i,  p.  713),  who  fed  their  nurslings  with  suitable 
bacteria  :    they  do  not,  however,  concern  us  here,  being  free-living  species. 

3  Compare     also     Quincke,     "  Ueb.     Protozocn-Enteritis "     (Berl.     klin.    Wchschr., 
1894,  Nos.  46  and  47). 

4  Jaeger,  H.,  in  C.  f.  B.,  P.  u.  I.,  xxxi.,  Orig.,  p.  551. 


AMOEBA    PULMONALIS         A.    UROGENITALIS  37 

2.  Amoeba  gingivalis,  Gros.J 

3.  Amoeba  buccalis,  Sternberg.- 

4.  Amoeba  dentalis,  Grass!.3 

Of  these  three  species  the  last  mentioned  may  certainly  be 
eliminated,  as  its  describer  has  himself  suggested  the  possibility  of 
having  mistaken  salivary  corpuscles  for  amoebae ;  the  other  two 
species  are  supposed  to  live  in  the  tartar  on  teeth.  They  have 
not  again  come  under  observation,  and,  on  the  other  hand,  Celli 
and  Fiocca  distinctly  state  that  they  have  never  found  amoeba-like 
organisms  in  the  oral  cavity. 

5.  Amoeba  pulmonalis,  Artault.4 

The  author  discovered  a  few  amoeboid  formations  with  nucleus 
and  vacuole  in  the  contents  of  a  lung  cavern.  In  the  fresh  condition 
they  were  distinguishable  from  leucocytes  by  their  remarkable 
capacity  of  light  refraction  ;  they  were  also  much  slower  than  the 
latter  in  staining  with  methylene  blue  or  fuchsine  ;  their  movements 
became  more  lively  in  a  strong  light.  Water  and  other  a*gents 
killed  them,  and  then,  even  when  stained,  they  could  not  be 
distinguished  from  leucocytes. 

6.  Amoeba  urogenitalis,  Baelz.5 

This  species  was  found  in  masses  in  the  sanguineous  urine  as 
well  as  in  the  vagina  of  a  patient  in  Japan,  aged  23,  in  whom, 
shortly  before  death  caused  by  pulmonary  tuberculosis,  haematuria 
with  severe  tenesmus  of  the  bladder  had  set  in.  The  amoeba, 
which  showed  great  motility,  and  had  a  diameter  of  about  0-050  mm. 
when  quiescent,  exhibited  a  granular  plasma  and  a  vesicular 
nucleus.  Baelz  is  of  opinion  that  these  parasites  were  introduced 
into  the  vulva  with  the  water  used  for  washing  the  parts,  and 
thence  penetrated  into  the  bladder  and  vagina. 

Similar    cases     are   also   reported   by   other   authors  :    Jurgens/'   Kartulis/ 


1  Gros,  G.,  "  Fragm.    d'helm.  et  de  phys.  microsc."    (Bull.  soc.  Imp.  d.  Natural,  de 
Moscou,  1849,  i  and  2,'  p.  555). 

2  Sternberg,  in  Zeitschr.  /.  neuere    Med.,   1862,  Nos.   20-24,  published  by  Walter, 
in  Kiew,  and  issued  in  the  Russian  language. 

8  Grassi,  B.,  in  Gazz.  med.  ital.  lomb  (8),  1879,  i.,  No.  45,  p.  445. 

4  Artault,  St.,  "  Flore  et  faune  d.  cav.  pulmon."  (Arch,  de  parasit.,  1898,  i.,  p.  275). 

5  Baelz,  E.,    "  Ueb.  einig.  neue  Paras,  d.  Mensch."  (Berl.  klin.  Wochenschr.,  1883, 
P-  237). 

ti  Jiirgens,  Deutsch.  med  Wochenschr.,  1892,  p.  454. 

'  Kartulis,  "  Pathog.  Protoz.  b.  Mensch."  (Zeitschr.  f.  Hyg.,  1893,  xiii-»  P-  2»  -^nm.  2). 


38  THE    ANIMAL    PARASITES    OF    MAN 

Posner,1  and  Wijnhoff.-,  Jiirgens  found  small  mucous  cysts,  filled  with 
amoeboid  bodies,  in  the  bladder  of  an  old  woman  suffering  from  chronic 
cystitis  ;  they  were  also  met  with  in  the  vagina.  The  amoebae  observed 
by  Kartulis  in  the  sanguineous  urine  of  a  woman,  aged  58,  suffering  from 
a  tumour  of  the  bladder,  measured  0*012 — 0*020  mm.,  and  exhibited  slow 
movements  by  protruding  short  pseudopodia.  The  vacuoles  and  nucleus 
became  visible  only  after  staining  with  methylene  blue. 

Posner's  case  related  to  a  man,  aged  37,  who  had  hitherto  been  quite 
healthy  and  had  never  been  out  of  Berlin.  Suddenly,  after  a  rigor,  he 
passed  urine  tinged  with  blood,  in  which  were  found,  besides  red  and 
white  blood  corpuscles  and  hyaline  and  granular  casts,  large  granular 
bodies  (about  0*050  mm.  in  length  and  0*028  mm.  in  breadth),  which 
slowly  altered  their  shape,  and  contained  red  blood  corpuscles  in  addition 
to  other  foreign  matter.  These  bodies  exhibited  one  or  several  nuclei  and 
some  vacuoles.  From  the  course  of  the  disease,  which  extended  over 
a  year,  and  during  which  similar  attacks  recurred,  Posner  came  to 
the  conclusion  that  the  amoebae  which  had  originally  invaded  the  bladder 
penetrated  into  the  pelvis  of  the  kidney,  where  they  probably  settled  in  a 
cyst,  and  thence  induced  the  repeated  attacks. 

Wijnhoff  observed  four  cases  of  amoeburia  in  Utrecht.3 

7.     Amoeba  kartulisi,  Dofl.4 

Kartulis5  observed  the  following  case  :  An  Arab,  aged  43, 
developed  an  abscess  as  large  as  an  orange  on  the  right  lower 
jaw,  with  a  fistulous  opening  secreting  a  thick  pus.  In  the  pus, 
as  well  as  on  pieces  of  bone  that  were  extracted,  amoebae  of 

0-030 — 0-038  mm.  in  diameter  were  found 
in  addition  to  bacteria.  The  movements 
of  these  amcebae  were  more  lively  than 
those  of  the  amoebae  of  dysentery ;  their 
coarsely  granular  protoplasm  contained  pus 
and  blood  corpuscles  ;  the  long  finger-like 
pseudopodia  were  very  rapidly  protruded, 
and  usually  appeared  singly ;  as  a  rule, 
the  very  small  nucleus  was  visible  only 

FIG.  5. — Amoeba  Kartuhsi 

Dofl.,  from  the  pus  of  a  sub-      after     staining,    and    in    like    manner    the 

Sa7faSutyn  7A°tUer     vacuo^s  also  escaped  observation. 
Kartulis.)  A    case    observed    by    Flexner6    also    deserves 

mention.      It    relates    to    a    man,   aged    62,  with 

1  Posner,  C.,  "    Ueb.  Amaeb.  i.  Harn"  (Berl.  klin.  Wochenschr.,  1893,  xxx.,  No.  28, 
p.  674). 

2  Wijnhoff,  J.  A.,  "  Over  amceburie  "  (Nederl.  Tij'dschr.  v.  Geneeskde,  1895,  P-  IO7)- 

3  The  amoeba-like  formations  found  by  Doria  on  the  floor  of  the  glands   in  endo- 
metritis  chronica  (Arch.  /.  Gyndkol.,   1894,  xlvii.,  p.    i)  are  regarded  by  Pick  (Berl. 
klin.  Wochenschr.,  1895,  NOS.  22  and  23)  as  altered  epithelial  cells. 

1  Doflein,  F.,  Die  Protoz.  als  Par.  u.  Krankheitserr.,  Jena,  1901,  p.  30. 

5  Kartulis,  "  Ueb.  pathog.  Prat.  b.  Mensch."  (Zeitschr.  f.  Hyg.,  1893,  xiii.,  p.  9). 

6  Flexner,  "  Amoeba  in  an  Abscess  of  the  Jaiv  "  (Johns  Hopk.  Hasp.  Bull.,  No.  2<(, 
1892)  ;    ref.  in  C.  f.  B.  u.  P.,  xiv.,  1893,  p.  288. 


AMOEBA    MIURAI  39 

an  abscess  on  the  floor  of  the  oral  cavity,  from  which  pus  was  artificially 
evacuated.  The  pus  in  addition  to  many  different  kinds  of  bacteria  also 
contained  amoebae.  These  amoebae  were  larger  than  leucocytes,  and  exhibited 
granular  plasm  and  vacuoles  ;  the  nucleus  could  not  be  distinctly  made  out. 

The  pseudopode  formation,  which  ceased  at  a  low  temperature,  could 
again  be  brought  into  play  by  warming  the  slide. 

Doflein  conjectures  that  in  both  the  cases  quoted  it  was  a  question  of 
dysenteric  amoebae,  though  there  was  no  history  of  previous  dysentery  in 
either  case.  It  has  long  been  known  that  Amoeba  dysenterica  appears  in 
dysenteric  hepatic  abscesses  and  in  the  secondary  pulmonary  abscesses 
that  occasionally  follow.  An  observation  by  Nasse,1  who  operated  on  a 
dysenteric  hepatic  abscess,  shows  that  the  amoebae  may  also  penetrate  still 
further.  In  this  case  gangrene  of  the  wound  subsequently  set  in,  and  the 
amoebae  were  found  not  only  in  the  hepatic  abscess,  but  subsequently  also 
in  the  wound,  in  the  skin,  and  even  in  the  muscular  system. 

The  "amoebae"  found  by  Berndt-  in  the  pus  from  a  hepatic  abscess 
(after  typhus)  appear  to  be  entirely  problematical  formations. 


8.    Amoeba  miurai,  Ijima.* 

Under  this  term  the  author  describes  protoplasmatic  bodies 
which  Miura,  in  Tokyo,  found  in  the  serous  fluid  of  a  woman, 
aged  26,  who  had  died  from  pleuritis  and  peritonitis  endothelio- 
matosa  ;  two  days  before  death  these  same  forms  had  also  appeared 
in  the  haemorrhagic  faeces  of  the  patient.  The  bodies  were 
usually  spheroid  or  ellipsoidal,  and  at  one 
pole  carried  a  small  protuberance  beset 
with  filamentous  short  pseudopodia,  re- 
sembling the  appendages  possessed  by 
free-living  amoebinae.  Their  size  varied 
between  0-015  and  0-038  mm.  ;  the 
plasma  was  finely  granular,  and  no  FlG  6._Ama}ba  miurai>  xj., 

difference   was  observable    in    the    ecto-      500/1:  (a)  fresh  ;  (6)  after  treat - 

n         _  i      ji         -n  i  ment    with   dilute    acetic  acid. 

and  endo-  sarc,  only  the  vinous  appendage      (After  ijima.) 

was  lighter  :  the  plasma  contained  vacuoles 

more  or  less  numerous,  none  of  which  were  contractile.     After  the 

addition  of  acetic  acid   one   to  three  nuclei   could  be  distinguished, 

0-008   to   0-015    m    size-      Actual    movements   were   not    observed. 

Taking    everything    into    consideration,  the    independent    nature   of 


1  Nasse,  "  Ueb.  ein.  Amcebenfund  b.  Leberabsc.  u.  Dys."  (Dtsch.  med.  Wochenschr., 
1891,  p.  881). 

*  Berndt,  F.,  "  Protoz.  in  ein.  Leberabsc."  (Dtsche.  Zeitschr.  f.  Chir.,  1895,  xl.,.p.i63). 

:'  Tjima,  ].,  "On  a  New  Rhizopod  Parasite  of  Man"  (Annot.  zonl.  japon,  1898, 
ii.,  3,  p.  85) ;  ref.  in  C.  /.  B.t  P.  u.  /.,  1899,  xxv.,  p.  885. 


40  THE    ANIMAL   PARASITES    OF    MAN 

these  bodies  is,  to  say  the  least,  doubtful,1  although  it  cannot  be 
denied  that  they  possess  a  certain  similarity  to  the  marine  Amoeba 
fluida,  Griiber  or  Greeff,  and  to  a  few  other  species. 

9.     Leydenia  gemmipara,  Schaud.- 

In  the  fluid  removed  by  puncture  from  two  patients  suffering 
from  ascites  in  the  first  medical  clinic  in  Berlin,  cellular  bodies 
with  spontaneous  movement  were  found  which  Leyden  and 
Schaudinn  regard  as  distinct  organisms.  They  remained  alive 
without  the  use  of  the  heated  object  table  for  four  or  five 
hours,  the  external  temperature  being  24  to  25°  C.  In  a 
quiescent  condition  they  were  of  a  spherical  or  irregular  poly- 
gonal form  ;  their  surface  was  rarely  smooth,  being  beset  with 


vl«fcv'»*>    *v*  '' 

-v-f 


1 

FIG.  7. — Leydenia  gemmipara,  Schaud.  :  (a)  In  a  quiescent  condition,  1,000/1  ;  (b)  in 
the  act  of  moving,  1,000/1  ;    (c)  a  preserved  specimen  with  bud,  1,500/1. 

protuberances  and  excrescences.  The  substance  of  the  body  was 
solid  and  permeated  with  light  refracting  nuclei  with  a  yellowish 
shimmer.  The  hyaline  ectosarc  was  rarely  seen  distinctly.  All 
sizes  from  0-003  to  0-036  mm.  in  diameter  were  observed.  The 
movements  were  rather  sluggish,  the  ectosarc  in  the  meantime 
appearing  in  the  form  of  one  or  several  large  lamellae  in  which 
also  strings  of  the  granular  endosarc  appeared,  and  frequently 
protruded  over  the  border  of  the  hyaline  pseudopod.  The 

1  Liihe  considers  Amoeba  miurai  to  be  "  exudation  cells  "  (C.  /.  B.,  P.  u.  I.,  1902, 
xxi.,  ref.,  p.  207). 

2  Leyden,  E.  v.,  and  F.  Schaudinn,  "  Leydenia  gemmipara,  ein  neuer  i.  d.  Ascites 
Fliiss.  d.  leb.  Mensch.  gef.  amcebentihnl.  Rhizopode  "   (Sitzungsber.  d.  K.  Pr.  Acad.  d, 
Wiss.  Berl.,  18^96,  xxxix.,  p.  951). 


FLAGELLATA  41 

tendency  for  the  conjunction  of  several  individuals  by  means  of 
their  pseudopodia,  was  so  marked  that  associations  ensued  similar 
to  those  known  in  free-living  rhizopods. 

The  plasma  enclosed  blood  corpuscles  as  well  as  numerous 
vacuoles,  one  of  which  pulsated  slowly  (every  quarter  of  an  hour), 
and  a  vesicular  nucleus  the  diameter  of  which  was  about  equal 
to  one-fifth  of  the  entire  body. 

Propagation  took  place  by  means  of  division  and  budding,  after 
previous  direct  division  of  the  nucleus.  The  buds  are  supposed 
to  repeatedly  divide  soon  after  their  appearance,  thus  giving  rise 
to  minute  formations  of  0-003  mm- 

There  was  a  suspicion  in  both  cases  that  the  ascites  was  asso- 
ciated with  malignant  neoplasms  in  the  abdomen,  and  autopsy 
verified  this  view  in  one  case. 

Notwithstanding  the  fact  that  after  this  publication  the  ascites  fluid  in 
analogous  cases  has  been  diligently  examined  for  Leydenia,  only  two  confirma- 
tory reports  exist  hitherto,  according,  to  my  knowledge.  One  is  due  to 
Lauenstein,1  the  other  to  Ley  den.*  The  latter  first  of  all  mentions  the 
fact  that  the  second  case  of  the  two  mentioned  above  also  came  to  the 
post-mortem  room  and  confirmed  the  correctness  of  the  diagnosis,  lie  also 
reports  that  in  a  large  number  of  cases  the  fluid  drawn  from  numerous 
ascites  patients  was  examined,  and  the  same  remarkable  cells  with  amoe- 
boid motion  were  repeatedly  found.  According  to  Ley  den  these  bodies  are 
so  characteristic  of  carcinomatous  ascites  that  he  succeeded  a  few  times  by 
means  of  their  presence  in  correctly  giving  a  decision  in  cases  of  doubtful 
diagnosis. 

Other  observers  regard  the  Leydenia  as  abnormally  altered  body-cells, 
such  as  are  apt  also  to  appear  in  the  exudations  of  other  diseases. 
L.  PfeifferJ  has  even  now  come  to  look  upon  the  amoeboid  forms,  which 
he  and  others  have  observed  in  the  vesicles  of  variola,  vaccine,  varicella, 
herpes,  &c.,  in  pus  and  pleuritic  effusion,  and  hitherto  regarded  as  para- 
sites, as  merely  "  exudation  cells."  * 

Class  II.     Flagellata  (Mastigophora), 

During  the  motile  part  of  their  life  the  Flagellata  possess  one  or  more 
flagella  which  serve  for  locomotion,  and  in  many  cases  also  for  the  capture 
of  food  ;  a  few  groups  (Euglenoidince ,  Choanoftagellata)  have  only  one 
flagellum,  others  two  or  several  of  about  equal  length  (Isomastigoda\  or 
of  various  lengths  (Monadina,  Heteromastigoda,  Dinoflagellatd}.  The  long 


1  Lauenstein,  C.,  "  Ueb.  ein.  Be  fund  von  '  Leyd.  gemmip.'  "     (Deutsch.  med.  Wochen- 
schr.,  1897,  xxiii.,  p.  733). 

-  Leyden,  E.  v.,  "  Z.  Aet.  d.  Carcin."  (Zeitschrift  /.  kl.  Med.,  1961,  xliii.,  p.  4)- 

3  Pfeiffer,  L.,   "  ref.  iib.  die  Leyden-Schaudinn' sche  Arbeit"  (Mi'mch.  med.  Wochen- 
schr.,  1896,  xliii.,  p.  894). 

4  Liihe  expresses  his  conviction  that  the  Leydenia  are  of  an  independent  nature 
(C.  f.  B.,  P.  u.  I.,  1902,  xxxi.,  ref.,  p.  207). 


42  THE   ANIMAL    PARASITES    OF    MAN 

flagellum  is  called  the  principal  flagellum  ;  the  smaller  ones  on  the  same 
creature  are  called  accessory  flagella.  The  flagella  directed  backwards,  which 
occur  in  the  Heteromastigodes  and  are  used  for  clinging,  are  termed  trailing 
flagella.  At  the  basis  of  the  flagella,  which  are  almost  always  at  the 
anterior  end,  the  Choanoflagellata  possess  a  plasmatic  funnel-shaped  neck. 
In  the  parasitic  forms  an  undulating  membrane  is  frequently  present. 

The  body  of  the  Flagellata  is  usually  small,  generally  elongated,  and  of 
unchangeable  form  ;  it  is  frequently  covered  by  a  distinct  cuticle,  and,  in 
certain  groups,  by  a  solid  armature,  or  it  may  be  more  or  less  loosely  envel- 
oped by  a  gelatinous  or  membranous  covering.  An  ectosarc  layer  is  not  usually 
observable.  The  granular  plasm  contains  a  varying  number  of  vacuoles, 
one  of  which  in  most  cases  is  always  contractile,  and  is  generally  situated 
at  the  place  from  which  the  flagella  arise,  that  is,  at  the  anterior  extremity. 
The  plasm,  moreover,  contains  the  nucleus,  which  is  nearly  always  single  ; 
and  in  many  species  there  are,  besides,  yellow,  brown,  or  green  chromatophores 
of  various  shapes,  such  as  occur  in  plants.  Some  species  feed  after  the  manner 
of  green  (holophytic)  plants,  or  of  plants  free  from  chlorophyll  (saprophytic)  ; 
others,  again,  ingest  solid  food,  and  for  this  purpose  usually  possess  a  cyto- 
stom  ;  the  latter,  however,  in  a  few  forms  is  not  used  for  its  original  function, 
but  is  connected  with  the  contractile  vacuole.  A  few  species,  such  as 
Trichocysts,  present  eye-spots  with  or  without  light-refracting  bodies. 

Propagation  takes  place  by  means  of  division,  mostly  longitudinal  division, 
and  after  previous  division  of  the  nucleus,  eventually  of  the  neck  and  the 
chromatophores.  The  flagella  during  this  process  appear  to  be  regularly  cast, 
so  that  each  daughter-individual  must  develop  fresh  flagella,  as  is  the  case 
with  the  cytostom.  Division  may  take  place  in  the  free  motile  condition, 
or,  in  the  encysted  state,  eventually  within  the  capsule.  Divisions  imper- 
fectly accomplished  give  rise,  to  colonies.  Copulation  from  time  to  time 
amongst  individuals  of  the  same  or  different  form  is  very  general  amongst 
the  flagellata.  The  product  of  copulation,  the  zygote,  becomes  parent  to  the 
free  motile  generation  by  means  of  successive  divisions  ;  this  affords  an 
alternation  of  generations,  as  the  latter  multiply  without  previous  copulation. 

Most  Flagellata  live  free  in  fresh  and  salt  water  ;  they  like  stagnant  water, 
and  are  found  in  waters  rich  in  organic  products  of  decomposition,  such  as 
puddles,  swamps  and  pools.  Those  forms  developing  shells  and  colonies 
are  as  a  rule,  adherent.  A  number  of  species  are  parasitic  in  man  and 
animals,  living  mostly  within  the  intestine  or  in  the  blood. 

It  is  usual  to  classify  the  Flagellata  into  four  orders  :  Euflagellata  t 
Dino  flagellata,  Choanoflagellata,  and  Cysto flagellata,  of  which  only  the  Euflagellata 
are  of  interest  to  us.  This  is  a  group  comprising  numerous  species,  for 
the  further  classification  of  which  the  number  and  position  of  the  flagella 
are  utilised. 

The  Euflagellata  observed  in  man  closely  approach  to  the  Protomonadines 
as  well  as  to  the  Polymastigines  ;  the  former  possess  either  only  one  or  two 
similar  flagella,  or  one  principal  and  one  or  two  accessory  flagella,  whereas 
the  Polymastigines  possess  at  least  three  flagella  of  equal  size,  or  four  to 
eight  of  unequal  size,  inserted  at  different  points.  An  undulating  mem- 
brane may  be  present  in  members  of  both  groups  ;  during  rapid  motion  it 
conveys  the  impression  of  a  row  of  cilia  and  has  often  been  mistaken  for 
the  latter. 


TRICHOMONAS    VAGINALIS  43 

It  must  also  be  pointed  out  that  unicellular  organisms  with  one  or 
several  flagella  are  not  always  classified  with  Flagellates,  for  such  forms 
occur  in  Rhizopods  as  well  as  transiently  in  the  lower  plants.  In  addition 
the  examination  of  the  Flagellates,  especially  the  parasitic  species,  is  very 
difficult  on  account  of  their  diminutive  size  and  great  activity  ;  thus  it  happens 
that  certain  forms  cannot  with  certainty  be  included  in  the  group  because 
their  description  is  insufficient. 

LITERATURE. 

BUTSCHLI,  O.     Protozoa  in  Bronn's  Cl.  u.  Ord.  d.  Thierr,  1880-87. 

KLEBS,  G.     Organisation  einig.  Flagellatengrupp.     (Unters.  a.  d.  bot.  Inst.  Tubing, 
1883,  i->  2  I    z-  f-  wiss-  Zool.,  1892,  Iv. 


BLOCHMANN,  F.     Mikrosk.  Thierw.  des  Susswassers.     2nd  edition,  1895. 
KENT,  S.     Manual  of  the  Infusoria.     London,  1  880-81,  i. 


A. — Polymastigina,  Blochm. 

The  Flagellata  parasitic  in  man,  and  best  known,  belong 
to  the  Polymastigines,  and  to  two  genera  that  are  easily  dis- 
tinguishable. 

Gen.   i.     Trichomonas,  Donne,   1837. 

The  body  is  generally  pyriform,  the  anterior  part  usually  rounded,  the 
posterior  part  pointed  ;  there  are  at  the  anterior  extremity  three  or  four  equally 
long  flagella  that  are  sometimes  fused  together ;  in  addition  there  is  an 
undulating  membrane  that  commences  at  the  anterior  extremity  and  proceeds 
obliquely  backwards.  The  nucleus  is  situated  at  the  anterior  extremity, 
and  behind  it  are  one  or  more  vacuoles,  none  of  which  seem  to  be  contrac- 
tile. These  flagellates  are  parasitic  in  vertebrate  and  invertebrate  animals, 
and  live  chiefly  in  the  intestine. 

I.     Trichomonas  vaginalis,  Donne. 

Form  of  body  very  variable,  elongated,  fusiform  or  pear-shaped, 
also  amoeboid ;  the  length  varying  between  0*015  and  0*025 
mm.,  and  the  breadth  between  0*007  and  0*012.  The  posterior 
extremity  is  drawn  out  to  a  point  and  is  about  half  the  length 
of  the  remainder  of  the  body.  Cuticle  very  thin  ;  the  body  sub- 
stance finely  granular.  At  the  anterior  extremity  there  are  three 
— some  say  four ] -^flagella  of  equal  length  which  are  frequently 
united  together,  at  least  at  the  base,  and  easily  fall  off. 

There  is  an  undulating  membrane  which  runs  spirally  across 
the  body,  arising  from  the  place  of  insertion  of  the  flagella,  and 
terminating  at  the  base  of  the  caudal  process.  Cytostom  seldom 


1  To  explain  this  discrepancy  it  is  stated  that  the  border  of  the  undulating  mem- 
brane can  raise  itself  off  in  the  form  of  an  independent  flagellum. 


44 


THE    ANIMAL    PARASITES    OF    MAN 


recognisable.     Nucleus  vesicular,  elongated,  situated  at  the  anterior 

extremity.1 

Propagation  takes  place  by  division  (Marchand)  ;  encysted  forms 

are   unknown. 

Trichomonas  vaginalis  lives  in  the  vaginal 
mucus  of  women  of  various  ages  ;  not  in 
normal  mucus,  but  in  mucus  of  acid  reac- 
tion. It  is  found  in  menstruating  females 
as  well  as  in  females  that  have  passed  the 
menopause  ;  it  is  found  in  pregnant  and  non- 

Pregnant    WOmen>    6Ven    in    V6ry    yOUnS    gMs> 

provided    always    that   they  have   a   vaginal 
catarrh   with   acid   reaction   of  the   secretion.      Should  the  acid  re- 
action change,  as,  for  instance,  during  menstruation,    the    parasites 
disappear,    as    they    do    likewise    on    injection 
of    any  alkaline    fluid  into    the  vagina  ;    a  low 
temperature  (below  +  15°  C.)  is  also  fatal  to  the 
parasites. 

Trichomonas  vaginalis  appeared  to  be  a 
parasite  specific  to  the  female  organs  and 
not  transmissible  to  man.  Recently,  how- 
ever, several  observations  have  been  made 
that  confirm  the  occurrence  of  this  species 
in  the  urethra  of  the  male.  The  infection 
apparently  takes  place  through  coitus  when 
changes  are  present  in  the  urethral  mucous 
membrane  ;  in  any  case  the  three  cases  observed 
point  to  this  circumstance.2 

Experimental  transmission  to  rabbits,  guinea- 
pigs  and  dogs  failed  (Blochmann,  Dock).  So 
far  the  manner  in  which  women  become  in- 
fected is  unknown. 


FIG.  g. — Trichomonas 
vaginalis,  D.,  high  mag- 
nification.  (After 
Kiinstler.) 


2.      Trichomonas  intestinalis,  R.  Lkt. 

Now  several    authors    believe    that    a  second 
trichomonade   inhabiting  man,   Trichomonas  intes- 


1  According  to  Marchand,  the  nucleus  is  connected  with  a  line,  which  becomes 
visible  on  addition  of  acetic  acid,  terminates  at  the  posterior  extremity,  and  does  not 
correspond  to  the  line  of  insertion  of  the  undulating  membrane.  This  formation 
probably  is  the  same  as  the  one  known  as  the  "  quill  "  in  Trichomonas  batrachorum, 
Perty.  Blochmann  also  mentions  two  longitudinal  rows  of  granules,  which  commence 
at  the  same  plane  as  the  nucleus  and  converge  towards  the  back. 

-  Donne,  A.  Rech.  sur  la  nature  du  mucus,  Paris,  1837  '>  Scanzoni,  F.  W.,  Beitr. 
z.  Gbrtskde.,  1855,  ii..  p.  131  ;  Scanzoni,  F.  W.,  and  A.  Kolliker,  "  Quelq.  rem.  sur  le 


TRICHOMONAS    INTESTINALIS  45 

tinalis,  R.  Lkt.,  is  identical  with  Trichomonas  vaginalis,  Donne. 
Leuckart's  species1  was  based  on  the  discoveries  of  Marchand  - 
and  Zunker,3  who  state  that  according  to  all  appearances,  and 
in  their  opinion,  it  is  the  same  as  Cercomonas  intestinalis, 
Lambl,  1875  (nee  1859),  which  they  found  in  the  faeces  of 
patients  suffering  from  intestinal  disorders.  The  organism  is 
described  by  them  as  being  0-01-0-015  mm.  in  length ;  the  posterior 
extremity  terminates  in  a  point,  while  a  row  of  twelve  or  more 
cilia  commence  at  the  anterior  end  and  extend  over  the  body. 
Leuckart  states  that  this  parasite  placed  by  the  two  authors 
with  the  Cercomonas,  is  a  Trichomonas,  that  they  mistook  the 
undulating  membrane  for  cilia,  and  overlooked  the  flagella.  Not- 
withstanding its  striking  similarity 
with  Tr.  vaginalis  it  is  distinguish- 
able from  this  species  by  the  con- 
siderably larger  number  of  parts 
(cilia)  composing  the  ciliated  crest 
(undulating  membrane).  Lambl's 
Cercomonas  intestinalis^  (of  1875) 
which  corresponds  with  Cercomonas 
hominis,  Davaine5  (1854),  is  re- 
garded by  Leuckart  as  a  true  CerCO-  FlG-  10.— Trichomonas  intestinalis, 
,  ;  ,  .  ,  ,  n  „  Lkt.  (after  Grass! ). 

monade  (characterised  by  a  flagellum 

and  the  absence  of  an  undulating  membrane)  thus  generically  distinct 

from  Trichomonas. 

The    correctness    of    Leuckart's    judgment    in    regard    to    Mar- 

Trich.  vag."  (C.  R.  Ac.  so.,  Paris,  1868,  xl.,  p.  1076)  ;  Hausmann,  Die  Paras,  d.  weibl 
Geschlechtsorg,  Berlin,  1870;  Blochmann,  F.,  "Bern.  iib.  einig.  Flagell."  (Z.  /.  w.  Z. 
1884,  xl.,  p.  42)  ;  Kiinstler,  J.,  "  Trichom.  vagin.,  D."  (Journ.  d.  microgr.,  1884,  vi"- 
p.  317)  ;  Marchand,  F.,  "  Ueb.  d.  York.  v.  Trick,  im  Harne  eines  Mannes  "  (C.  /.  B.  u.  P. 
1894,  xv.,  p.  709)  ;  Miura.  K.,  "  Trick  vag.  im  frisch  gelass.  Urin  eines  Mannes  "  (ibid. 
1894,  xvi.,  p.  67)  ;  Marchand,  F.,  "  Bern  z.  d.  vorsteh.  Arbeit  "  (ibid.,  p.  74)  ;  Dock,  G. 
"Flag.  Protoz.  in  the  Freshly  Passed  Urine  of  a  Man"  (Med.  News,  1894,  Ixv. 
p.  640)  ;  Dock,  G.,  "  Trichom.  as  a  Paras,  of  Man  "  (Am.  Journ.  Med.  Sc.,  1896 
p.  i)  ;  Laveran,  A.,  and  F.  Mesnil,  "  Sur  la  Morph.  et  la  syst.  d.  Flag.,  d  membr.  ondnl." 
(C.  R.  Ac.  sc.,  Paris,  1901,  cxxxiii.,  p.  131). 

1  Leuckart,  R.,  Die  Parasiten  d.  Mensch.  (Lpzg.  1879-86,  i.,  2nd  edition,  p. 
315). 

*  Marchand,  "  Bin  Fall  von  Infusorien  im  Typhusstuhl  "  (Virchow's  Arch.  /.  path. 
Anat.,  1875,  ixiv.,  p.  293). 

3  Zunker,  "  Ueb.  d.  York.  d.  Cercom.  intestinalis  -  im  Digestionscanal  des  Menschcn  " 
Deutsch.  Ztschr.  f.  pract.  Med.,  1878,  p.  i.) 

1  Under  the  terra  Cercomonas  intestinalis,  Lam,bl  in  different  years  has  described 
two  entirely  distinct  flagellata,  namely,  in  1859  (Mikr.  Unters.  d.  Darm-  Excrete.  Prag 
Vierteljahrsschr.  f.  prakt.  Hlkde.,  Ixi.,  p.  51  ;  and  Lambl  A.  d.  Franz- Josephs-Kinderspitalc 
in  Prag.,  Prag.,  1860,  i.,  p.  360),  a  form  that  we  at  the  present  day  term  Lamblia  intes- 
tinalis ;  and  in  1875  (in  the  Russian  Medical  Report,  No.  33),  a  species  identical  with 
Cercomonas  hominis,  Dav. 

5  Davaine,  C.,  "  Sur  les  anim.  in/us,  trouv.  dans  les  selles  d.  malad.  atteints  du  chol.'-rn 
et  d'aiitr.  malad."  (C.  R.  soc.  biol.,  1854,  ii.,  p.  129). 


46  THE    ANIMAL    PARASITES    OF    MAN 

chand-Zunker's  Flagellate  was  soon  demonstrated  by  Grassi's1 
researches,  accounts  of  which  were  published  soon  after.  In  about 
100  cases  of  bowel  complaints  in  North  Italy  and  Sicily,  Grassi 
found  Flagellata  in  the  stools,  which  he  first  named  Monocerco- 
monas  and  Cimcenomonas,  but  later,  however,  termed  Trichomonas . 
However,  in  opposition  to  Leuckart,  Grassi  has  also  classified 
Davaine's  Cercomonas  hominis  (  =  Cere,  intestinalis,  Lambl,  1875)  as 
Trichomonas,  and  most  authors  have  followed  his  example.  It  is 
only  recently  that,  through  Janowski,-  the  former  standpoint  has 
again  been  taken  up.  After  a  thorough  review  of  the  literature, 
the  occurrence  of  Cercomonades  in  the  intestine  of  human  beings, 
in  addition  to  Trichomonades,  is  considered  by  the  author  to 
have  been  proved,  and  he  adds  a  minute  description  of  the 
Trichomonades.  According  to  this,  as  well  as  according  to  the  state- 
ments of  earlier  authors,  all  morphological  distinction  between  Tricho- 
monas vaginalis,  Donne,  and  T.  intestinalis,  Leuckart,  disappears. 
No  importance  can  any  more  be  attached  to  the  greater  number 
of  the  cilia  which,  according  to  Leuckart,  were  nothing  more 
nor  less  than  an  impression  conveyed  by  the  movements 
of  the  undulating  membrane ;  therefore  Leuckart' s  designation 
must  give  way  to  Donne's  older  term,  and  the  Trichomonade 
occurring  in  the  intestine  of  man  must  be  called  Trichomonas 
vaginalis,  Donne. 

In  the  same  way  other,  names  applied  to  this  species  become 
synonyms,  the  following,  for  instance  :  Protoryxomyces  coprinarius, 
Cunn.,  1881 ; 3  Monocercomonas  hominis,  Grassi,  1882 ;  Cimcvnomonas 
hominis,  Grassi,  1882  ;  Trichomonas  hominis,  Grassi,  1888  ;  Cercomonas 
coli  hominis,  May,  1891 ; 4  Monocercomonas  hominis,  Epstein.5 

It  therefore  follows  that  the  species  here  discussed  is  found 
not  only  in  the  vagina  of  women,  in  the  urethra  of  men,  and  in 
the  small  and  large  intestines  of  healthy6  and  sick  persons,  but 


1  Grassi,  B.,  "  Int.  ad.  ale.  prot.  entopar.  "  (Atti  soc.  ital.  sc.  nat.  Milano,  1882, 
xxiv.,  p.  135)  ;  "  Signific.  pathol.  del  protoz.  par.  dell'  uomo  "  (Atti  R.  Accad.  d.  Lincei. 
Rendic.,  iv.,  1888,  p.  83) :  "  Sur  quelq.  prot.  endop.  .  .  "  (Arch.  ital.  de  biol.,  1882,  ii., 
p.  402  ;  1883,  iii.,  p.  23). 

-Janowski,  W.,  "  Flagell.  i.  d.  menschl.  Faces"  (Zeitschr.  f.  klin.  Med.,  1887, 
xxxi.,  p.  442). 

3  Cunningham,  D.  D.,  "On  the  Development  of  Certain  Microscopical  Organisms 
Occurring  in  the  Intestinal  Canal  "  (Quar.  Journ.  of  Micros.  Sc.,  1880,  2,  xxi.,  p.  234  ; 
Zeitschr.  fi'ir  Biolog.,  1882,  viii.,  p. •251). 

1  May,  "  Ueber  Cercom.  coli  horn."  (Dtsch.  Arch.  f.  klin.  Med.,  1891,  xlix.,  p.  51). 

•'  Epstein,  A.,  "  Beob.  ilber  Monocerc.  horn.  u.  Amoeba  coli  "  (Prag.  med.  Wochenschr., 
1893,  Nos.  38-40). 

6  Schuberg,  A,,  "Die  paras.  Amceb.  d.  menschl.  Darmes  "  (C.  f.  B.  u.  P.,  1893, 
xiii.,  p.  598)  ;  Boas,  Dtsch.  med.  Wochenschr.,  1896,  p.  2-4. 


TRICHOMONAS  PULMONALIS  47 

has  also  been  observed  in  the  stomach  and  in  the  oral  cavity : 
in  the  stomach  by  Strube,1  in  the  oral  cavity  of  a  typhoid 
patient  and  in  that  of  a  healthy  person  by  Rappin,2  as  well  as 
by  Zunker  in  one  of  his  patients.  The  Trichomonades  that  have 
been  observed  by  Steinberg3  in  the  oral  cavity  of  man,  and  which 
he  regards  as  belonging  to  three  different  species  (T.  elongata, 
T.  caudata,  and  T.  flagellata,  and  perhaps  also  his  Cercomonas 
bi  flagellata),  are  certainly  specimens  of  T.  vaginalis,  s.  I.4  The  same 
may  be  said  of  the  flagellata  observed  in  the  lung  or  in  the  expec- 
toration, and  which  have  received  the  name  of 

3.     Trichomonas    pulmonalis. 

Two  authors  make  use  of  this  designation,  A.  Schmidt5  and 
St.  Artault  ;G  the  former  found  the  Trichomonades  exclusively 
in  the  so-called  Dittrich's  grafts,  together  with  various  bacteria ; 
the  latter  found  the  parasites  in  the  contents  of  a  large  vomica. 
In  this  connection  we  may  refer  to  an  old  communication  of 
Leyden  and  Jaffe,7  who  likewise  observed  "  infusoria "  in  the 
putrid  sputum  of  persons  suffering  from  gangrene  of  the  lungs 
and  putrid  bronchitis  (compare  p.  53  as  to  the  occurrence  of 
Cercomonades  in  gangrene  of  the  lungs). 

It  is  evident,  therefore,  that  Trichomonas  vaginalis  finds  the  con- 
ditions necessary  to  its  existence  in  various  organs  of  man  "that  are 
accessible  from  the  outside.  It  has  not  yet  been  established  in 
what  condition  and  by  which  means  the  parasites  are  able  to  find 
entrance  into  man.  Transmission  to  mammals  (per  os)  has  proved 
negative.  Their  occurrence  in  the  oral  cavity,  and,  still  more, 
their  presence  in  the  lungs,  seems  to  point  to  the  air  as  the 
vehicle,  and  their  presence  in  the  intestine  does  not  contradict 
this  view.  Others  incriminate  drinking  water,  and  an  observation  of 
Epstein  (I.e.)  seems  to  support  this  opinion.  In  a  room  in  Epstein's 


1  Strube,  G.,  Trick,  horn,  im  Mageninhalt  bei  Carcinoma  cardia  "  (Berl.  klin. 
Wochenschr,  1898,  p.  708). 

-  Rappin,  G.,  Contrib.  a  Vttude  des  baot.  de  la  bouche  a  I' Hat  norm,  et  dans  la  fievre 
typhoide,  These,  Paris,  188.1. 

:<  Steinberg,  Kiewer  Ztschr.  /.  neuere  Med.,  1862. 

1  It  appears  that  Home  (Chem.  u.  Mikrosk.  am  Krankenbett,  Erl.,  1850,  p.  61)  and 
Langeraux  (Traite  d'an.  path.,  i.,  p.  777)  long  ago  observed  Trichomonades  in  the 
oral  cavity. 

•'Schmidt,  A.,  "  Ueb.  paras.  Protoz.  i.  Auswurf "  (Miinch.  med.  Wchschr.,  1895, 
No.  51). 

H  Artault,  St.,  "  Flore  et  faune  d.  Cavern,  pulm."  (Arch.  d.  parasit.,  1898,  i.,  p.  217). 

?  Leyden  and  Jaffe,  "  Ueb.  putr.  (foet.)  Sputa  nebst  einig.  Bemerk.  ub.  Lungenbrand  it. 
putr.  Bronchitis  "  (Dtsch.  Arch.  f.  klin.  Med.,  1867,  p.  488). 


48  THE   ANIMAL   PARASITES    OF    MAN 

clinic  occupied  by  four  children,  three  who  partook  of  the  general 
diet  as  well  as  of  water  fell  ill  of  diarrhoea  with  Trichomonades, 
whereas  the  fourth  child,  who  did  not  drink  water,  remained  well. 
When,  however,  this  child,  as  a  matter  of  experiment,  was  twice 
given  250  c.cm.  of  the  same  water  that  the  other  children  had 
had,  he  likewise  became  ill.  According  to  another  opinion  the 
Trichomonades  are  innocuous  inmates  of  the  intestines  of  many 
healthy  persons,  and  appear  alive  in  the  fasces  whenever,  from  any 
cause,  there  is  increased  peristaltic  action  of  the  bowels.  It  is, 
however,  not  beyond  the  bounds  of  possibility  that  in  intestinal 
disturbances,  the  Trichomonades,  by  increasing  rapidly,  may  aggra- 
vate, or  at  least  protract,  the  morbid  process. 

May,  Roos,1  and  Schiirmayer-  state  that  they  have  seen 
encysted  forms,  but  it  is  not  certain  whether  these  really  belong 
to  Trichomonas. 

Kunstler  has  published  an  account  of  the  more  minute  struc- 
ture of  the  Trichomonades  (Observ.  sur  le  Trich.  intest.  in  Bull, 
scientif.  de  la  France  et  de  la  Belg.,  1898,  xxxi.). 

Gen.  2.     Lamblia,  R.  Blanch.,   1888. 

Syn.,  Dimorphus,  Grassi,  1879,  nee  Haller,  1878  ;  Megastoma,  Grassi,  1881, 
nee  de  Blainville. 

The  body  is  pear-shaped,  with  a  hollow  on  the  inferior  surface  directed  to 
the  front.  It  has  four  pairs  of  flagella  directed  backwards,  of  which  three 
pairs  lie  on  the  borders  of  the  hollow,  and  the  fourth  arises  from  the  pointed 
posterior  extremity. 

i.     Lamblia  intestinalis  (Lambl),  1889. 

Syn.,  Cercomonas  intestinalis,  Lambl,  1859  (nee  1875)  >  Hexamitus 
duodenalis,  Davaine,  1875  ',  Dimorphus  muris,  Grassi,  1879  ;  Megastoma 
entericum,  Grassi,  1881  ;  Megastoma  intestinale,R.  Blanch.,  1886. 

Length,  o-oi — 0-021  mm.  ;  greatest  breadth,  0*005 — 0-012  ; 
flagella  of  about  equal  length  (0-009 — 0^014  mm.). 

The  body  is  finely  granular  and  has  a  very  thin  cuticle, 
which  does  not  entirely  prevent  changes  of  form  of  the  body  ; 


1  Roos,  E.,  "  Ueb.  Infus.-Diarrhoe  "  (Dtsch.  Arch.  f.  klin.  Med.,  1893,  li.,  p.  505). 

-  Schiirmayer,  B.,  "  Ueb.  d.  York.  d.  Flagell.  i.  Darmk.  d.  Mensch."  (C.  f.  B.  u.  P., 
1895,  i,  xviii.,  p.  324).  For  further  literature  see  Janowsky  (/.  c.).  To  Schiirmayer 
the  credit  is  due  of  rediscovering  the  Trichomonade  of  the  human  intestine,  although 
in  the  single  work  which  he  consulted,  Leuckart's  Trichomonas  intestinalis  is  men- 
tioned a  few  lines  before  the  place  he  referred  to,  and  on  the  same  page  (Leunis, 
Svnops.  bearb.  v.  H.  Ludwig,  1886,  ii.,  p.  1125).  Fortunately  chance  led  our  author 
to  use  the  same  name  for  his  apparently  new  species,  although  in  it  he  did  not  find  the 
undulating  membrane. 


LAMBLIA   INTESTINALIS 


49 


the  very  motile  tail-like  appendix  in  the  frontal  plane  is  flattened. 
The  excavation  at  the  anterior  extremity,  which  is  directed  obliquely 
forward  and  with  its  border  projecting  backwards  and  interrupted, 
no  doubt  corresponds  to  the  peristoma  and  serves  as  a  clinging 
organ.  The  first  pair  of  flagella  (anterior  flagella)  arise  from  its 
anterior  edge,  the  second  and  third  pairs  (lateral  and  median 
flagella)  from  the  posterior  edge,  whereas  the  tail  flagella  are 
inserted  at  the  posterior  end  of  the  tail.  In  life  the  anterior 
and  lateral  flagella  sway  only  with  the  thinner  part  projecting 
beyond  the  body  ;  in  the  rest  of  their  course  they  appear  to  be 
almost  attached  to  the  body  ;  the  median  and  tail  flagella  are  quite 
free.  There  are  knob-like  formations  at  their  origin.  The  entire 
flagellate  apparatus  appears  to  be  connected  with  the  nucleus. 


FIG.  ii. — Lamblia  intestinalis,  from  the  surface,  from  the  side,  on  intestinal  epithe- 
lium ceils,  dead  and  encysted.    (After  Grassi  and  Schewiakoff. ) 


The  nucleus  is  of  a  dumb-bell  shape,  has  a  nucleolus  in  each  half, 
and  lies  anteriorly  in  that  part  of  the  body  that  is  excavated. 
Division  forms  have  not  been  observed,  but  there  are  encysted 
stages.  The  oval  cysts  (fig.  n)  measure  o-oi  mm.  in  length 
by  0-007  mm-  in  breadth,  they  are  surrounded  by  a  fairly  thick 
hyaline  layer,  through  which  the  contour  of  the  creature  can  some- 
times be  seen  quite  distinctly. 

Lamblia  intestinalis  inhabits  the  anterior  part  of  the  small  intestine  of 
various  mammals  (species  of  Mus  and  Arvicola,  rabbit,  domestic  dog  and  cat, 
sheep)  and  of  man.  Encysted  forms  are  found  in  the  colon  and  in  the 
faeces.  If  there  is  increased  intestinal  peristaltic  movement  the  free  forms 
also  appear  in  the  evacuations,  in  which,  however,  they  perish  if  kept  long* 
especially  if  the  temperature  is  lowered  to  o°  C.  or  raised  above  40°  C. 
Although  they  frequently  appear  in  large  numbers  they  cause  no  dis- 
order ;  at  all  events,  hitherto  no  stringent  reasons  have  been  brought  for- 
ward to  cause  the  Lamblia  to  be  considered  pathogenetic.  On  the  other 

4 


5O  THE   ANIMAL    PARASITES    OF    MAN 

hand,  the  fact  that  they  are  observed  not  only  in  persons  suffering  from 
intestinal  disorders,  but  also  in  other  diseases,  as  well  as  in  perfectly 
healthy  persons,  proves  their  innocuousness. 

The  infection  occurs  by  ingesting  the  encysted  forms,  a  fact  which  Grassi 
confirmed  on  his  own  person.  Cereals,  or  food  prepared  from  cereals,  polluted 
with  Lamblia  by  animals  living  in  the  vicinity  of  human  dwellings  (mice, 
rats),  are  probably  the  vehicles  by  which  they  are  introduced  into  man. 

The  parasite  under  discussion  was  first  observed  by  Lambl1 
in  the  mucous  evacuations  of  children.  He  regarded  the  parasite 
as  a  Cercomonade  and  termed  it  Cercomonas  intestinalis,  which 
name  as  a  rule .  is  applied  to  Cercomonas  hominis,  Davaine,  although 
Stein2  had  already  pointed  out  the  difference  of  the  two  species. 
Grassi  observed  this  species  first  in  mice  (Dimorphus  muris),  and 
subsequently  in  human  beings  in  Upper  Italy,  and  named  it 
Megastoma  entericum?  Biitschli4  and  Blanchard5  then  laid  stress 
on  the  identity  of  this  species  with  Lambl's  Cercomonas  intestinalis 
(1859),  and  consequently  called  it  Megastoma  intestinale.  Lastly, 
Blanchard 6  drew  attention  to  the  circumstance  that  the  specific 
name  (Megastoma)  chosen  by  Grassi  had  already  been  used  four 
times  m  to  specify  various  kinds  of  animals,  and  proposed  the 
denomination  Lamblia.  Accordingly  Lamblia  intestinalis  is  the 
only  term  that  holds  good,  and  should  be  generally  adopted. 

In  Upper  Italy  the  parasite  in  the  encysted  condition  has  also 
been  seen  by  Perroncito7  in  man.  At  the  same  time,  Grassi  and 
Schewiakoff8  undertook  a  new  examination  of  specimens  from 
mice  and  rats.  In  Germany,  Lamblia  intestinalis  was  found  by  Moritz 
and  Holzl,9  Roos,10  Schuberg11  and  Salomon12  and  Moritz  and  Holzl 


I  Lambl,  "  Unters.  d.  Darmexcrete  "  (Vierteljahrsschr.  /.  prakt.  Hlkde.,  Prag.,  1859, 
Ixi.,  p.  51  ;    Aus  d.  Franz- Jos. -Kinder  spit,  in  Prag.,  i.,  Prag.,  1860,  p.  360). 

•  Stein,  F.  v.,  Der  Org.  d.  In/us.,  III.  D.  Org.  d.  Flagell,  1878,  i.,  p.  80. 

3  Grassi,  B.,  "  Dei  protoz.  par.  e.   spec,  di  quelli  che  sono  nell'  uomo  "  (Gazz.  med. 
ital.    lomb.,  Milano,    1879,  No.  45);     "  Di  un  nuovo  paras,   dell'  uomo  (Meg.  enter.)'1 
(Gazz.  degli.  ospit.,   1881,  ii.,  Nos.    13-15);     "  Interno  ad  ale.    prot.  endop."   (Atti  soc. 
ital.  sc.  nat.,  1882,  xxiv.)  ;   '\Surquelq.  prot.  endop."  (Arch.  ital.  de  Hoi.,  1882,  ii.,  p.  421). 

4  Biitschli,  O.,  Protozoa  in  Bronn's  Cl.  u.  Ord.  d.  Thierr.,  1884,  p.  843. 

5  Blanchard,  R.,  TraiM  de  Zool.  med.,  Paris,  1885,  i,  i.,  p.  91. 

6  Blanchard,  R.,    "  Rem.  sur  le  Megast.  int."  (Bull.  soc.  zool.,  France,   1888,  xiii., 
p.  18). 

7  Perroncito,  E.,  "  Ueber  d.  Einkaps.  d.  Megast.  intest."  (C.  f.  B.  u.  P.,   1887,  ii., 
p.  738),  and  Giorn.  R.  Accad.  med.,  Torino,  1887. 

8  Grassi,  B.,  and  W.  Schewiakoff,  "  Beitr.  z.  Kcnntn.  d.  Meg.  ent."  (Z.  f.  wiss.  Zool., 
1888,  xlvi.,  p.  143). 

9  Moritz,  E.,  and  Holzl,  "  Ueb.  Haitf.  u.  Bedeut.  d.   York.  d.  Meg.  enter,  i.  Darmk. 
d.  Menschen"  (Munch,  med.   Wochenschr.,   1892,  xxxix.,  No.  47;   Sitz.-Ber.  d.Artzl.,^ 
Ver.  in  Munch.,  1893,  ii.,  p.  89). 

10  Roos,  "  Ueb.  Infus.-Diarrh."  (Dtsch.  Arch.  f.  klin.  Med.,  1893,  »•>  P-  5°5)- 

II  Schuberg,  A,,  "  Ref.  fiber  die  Arbeit  von  Moritz  u.  Holzl"  (C.  f.  B.  u.  P.,  1893, 
xiv.,  p.  85). 

12  Salomon,  H.,    "  Ueb.  ein.  Fall  von  Infusorien-Diarrh."  (Bcrl.  Klin.  Wochenschr., 
1899,  No.  46);    Quincke,  H.,  "  Ueb.,  Protozoan-Enteritis"  (ibid.,  Nos.  46-47). 


PROTOMONADINA  5! 

confirmed  the  relative  frequency  of  the  species.  In  Konigsberg, 
Prussia,  a  student  found  encysted  Lamblice  in  his  faeces.  One 
case  is  reported  from  Finland  by  Sievers,1  another  case  from  Scan- 
dinavia by  Miiller.2  Frshezjesski*  reports  cases  from  Russia,  but 
I  have  not  had  the  opportunity  of  reading  his  article  on  the  sub- 
ject. Jaksch4  announces  the  occurrence  of  the  parasite  in  Aus- 
tria ;  Piccardi 5  mentions  their  presence  again  in  Italy ;  and  we 
hear  of  them  in  Egypt  from  Kruse  and  Pasquale.6  Finally,  the 
structure  of  Lamblia  intestinalis  has  been  recently  described  by 
Metzner.7 


B.  Protomonadina,  Blochm. 

The  diminutiveness  of  the  Protomonadines  and  their  less  super- 
ficial situation  than  the  Polymastigines,  is  the  cause  that,  at  least 
in  regard  to  the  species  occurring  in  man,  they  are  very  little 
known.  As  regards  parasitical  species,, this  group  maybe  divided 
as  follows,  according  to  the  number  of  flagella  and  the  presence 
or  absence  of  an  undulating  membrane  :— 

(1)  Cercomonadidtz,  with  one  flagellum  at  the  anterior  extremity,  without 
an  undulating  membrane. 

(2)  Bodonidte,   with   two   flagella,   without   an   undulating  membrane. 

(3)  Trypanosomida,    with    one    flagellum    and    an    undulating    membrane 
along  the  entire  length  of  the  body. 

i.  Cercomonas  hominis,  Davaine,  1854. 

Davaine 8  found  Flagellata  in  the  evacuations  of  cholera  patients. 
They  had  pear-shaped  bodies  elongated  to  a  point  posteriorly. 
Their  length  averaged  from  O-QIO — 0-012  mm.,  and  a  flagellum 


1  Sievers,  "  Balant.  coli,  Meg.  ent.  u.  Bothr.  latus  bei  ders.  Pers."  (Ztschr.  /.  klin. 
Med.,  1896,  xxxiii.,  p.  25). 

-  Miiller,  E.,  "  Cercom.  intest.  i.  jejunum  fran  mdnn.  "  (Nord.  med.  ark.  1889,  xxi., 
No.  21 )  ;  Forhdlg.  biol.  Fo'ren.,  Stockholm,  1890,  ii.,  p.  42  ;  ref.  in  C.  /.  B.  u.  P.,  1890, 
viii.,  p.  592. 

3  Frshezjesski,  "  Ueb.  d.  Rolle  d.  Meg.  enter,  bei  chronisch.  Darmcatarrh."    (Russk. 
Arch.  Patol.,  klin.  Med.  i.  Bakt.,  1897,  ii.). 

4  Jaksch,  v.,  "  Ueb.  d.  York.  v.  thier.  Paras,  in  d.  Faces  d.  Kind  "  (Wien.  kl.  Wochen- 
schr.,  1888,  No.  25,  p.  511). 

5  Piccardi,    "Ale.  prat,  delle  fed  del  I'uomo  "  (Giorn.  R.  Accad.  med.,  Torino,  1895, 
Iviii.,  i);    Progr.  medical,  1895,  No.  23,  p.  377. 

0  Kruse,  W.,  and  A.  Pasquale,  "  Unters.  ub.  Dysent.  u.  Leberabscess  "  (Z^chr.  /. 
Hyg.,  1894,  xvi.,  p.  19). 

7  Metzner,  R.,  "  Unters.  an  Meg.  enter,  a.  d.  K  ani,nchendarm  "    (Ztschr.  /.  w.  Zoo., 
1901,  Ixx.,  p.  299). 

8  Davaine,  C.,  "  Sur  des  animalcules  in/us,  trouv.  dans  les  selles  d.  mal.  att.  du  chol, 
et  d'autres  mal."    (C.  R.  soc.  biol.,  Paris,  1854,  2.  *•>  P-  I29)- 


52 


THE    ANIMAL    PARASITES    OF    MAX 


twice  as  long  as  the  body  was  carried  at  the  rounded  extremity  ; 
a  nucleus  was  barely  recognisable  ;  occasionally  a  longish  forma- 
tion (cytostom  ?)  appeared  at  the  anterior  extremity.  The 
creatures  moved  with  remarkable  activity,  they  also  attached 
themselves  by  means  of  their  posterior  extremity  and  swung  about 
around  the  point  of  attachment.  Davaine  found  a  smaller 
variety  in  the  dejections  of  a  typhoid  patient  (fig.  12,  b). 


FIG.  12.  —  Cercomonas  hominis,  Dav.  (a) 
Larger,  (b)  smaller  variety.  Enlarged  (after 
Davaine). 


FIG.  13.  —  Cercomonas  hominis, 
Dav.  From  an  Echinococcus 
cyst  (after  Lambl). 


The  Flagellata  observed  by  Eckerkrantz  l  in  the  intestine  of  man  belong 
to  this  form  —  at  least  to  the  larger  variety  —  and  Tham  a  reported  fresh  cases 
soon  after.  Lambl's  publication3  of  1875,  which  was  written  in  Russian, 
and  became  known  through  Leuckart's  work4  on  parasites,  also  alludes  to 
apparently  typical  cercomonades,  which,  however,  were  discovered,  not  in 
the  intestine,  but  in  an  Echinococcus  cyst  in  the  liver.  The  elliptical,  fusi- 
form, rarely  pear-shaped  or  cylindrical  bodies  of  the  parasites  measured 
croo5  —  o-oi4  mm.  in  length,  and  were  provided  with  a  nagellum  at  one 
extremity,  while  the  other  extremity  usually  terminated  in  a  long  point. 
An  oral  aperture  existed  at  the  base  of  the  flagellum,  and  there  were  one 
or  two  vacuoles  about  the  posterior  extremity.  Longitudinal  division  was 
also  observed  (fig.  13). 

As  already  mentioned,  this  form,  which  Lambl  termed  Cerco- 
monas intestinalis,  differs  considerably  from  the  form  found  by 
the  same  author  in  1859,  which  received  the  same  designation 
(cf.  Lamblia  intestinalis),  but  it  corresponds  with  Cercomonas 
hominis,  Davaine.  The  latter,  as  well  as  Cercomonas  intestinalis, 
Lambl,  1879,  are  usually  classed  with  the  Trichomonades,  but,  as 
has  already  been  remarked  (cf.  Trichomonas  intestinalis),  this  cannot 
be  considered  correct,  as  only  one  flagellum  is  present. 

According  to    Janowski,    typical   Cercomonades  have    also   been 


1  Eckercrantz,  "  Bidr.  t.  kdnned.  om  de  i  mennisk.  tarmkan.  fo'rek.  infus."  (Nord, 
med.  Ark.,  1869,  i.,  No.  20  ;  Virchow-Hirsch's  Jahresber.,  1869,  i.,  p.  202). 

'  Tham,  P.  V.  S.,  "  Tvanne  fall  of  Cercom."  (Upsala  Idkarefor.  fb'rhdlg.,  1870,  v., 
p.  691  ;  Virchow-Hirsch's  Jahresb.,  1870,  i.,  p.  314). 

3  Lambl,    "  Cercomonas    et    Echinococcus    in  hepate   hominis  "    (Medic.    Wjestnik., 
1875,  No.  33). 

4  Second  edition,  vol.  i.,  p.  308. 


CERCOMONAS     HOMINIS  53 

observed  in  the  intestine  of  man  by  Escherich,  also  by  Cahen,1 
Massuitin, 2  Fenoglio,3  Councilman  and  Lafleur,4  Dock,5  Kruse  and 
Pasquale,6  Zunker,7  as  well  as  Quincke  and  Roos.8  However, 
it  is  an  open  question  whether  the  Flagellata  observed  by  Roos9 
in  one  of  his  cases  belonged  to  Davaine's  species,  the  size  shows 
some  deviation  (0-014 — o-oi6  mm.).  In  this,  as  in  many  other 
cases,  doubts  have  been  raised  as  to  whether  the  Flagellates 
found  in  the  stools  had  actually  lived  in  the  intestine,  or  had 
subsequently  appeared  in  the  faeces  :  for  this  a  surprisingly 
short  time  only  is  necessary.  Salomon  also  appears  to  have 
observed  Cercomonades  (Berl.  klin.  Wchschr.,  1899,  No.  46). 

As  with  Trichomonas  vaginalis  so  with  Cercomonas  hominis,  it 
appears  that  the  parasite  settles  not  only  in  the  intestine  but 
also  in  the  air-passages  ;  this  is  demonstrated  by  the  statements 
of  Kannenberg  10  and  Streng  H  of  the  occurrence  of  Monades  and 
Cercomonades  in  the  sputum  and  putrid  expectoration  in  gan- 
grene of  the  lungs,  which  no  doubt  apply  to  Cercomonas  hominis 
(cf.  also  Artault).12  Possibly  also  the  Flagellata  observed  in  the 
pleural  exudation  by  Litten 13  and  Roos 14  may  be  here  included ; 
this  is  the  more  probable  in  Roos's  case,  as  here  the  process  ensued 
in  the  pleura  after  the  breaking  through  of  a  vomica.  Perroncito 15 
and  Piccardi 16  describe  the  encysted  stages  of  the  Cercomonades. 


1  Cahen,  "  Ueber  Protoz.  in  kindl.  Stuhl  "  (Dcutsch.  med.  Wochenschr.,  1891,  No.  27, 
P-  853). 

2  Massuitin,  "  Amceben  als  Parasiten  des  Dickdarms."  (Wratsch.,  1889,  No.  25  ;   Cen- 
tralbl.  fiir  B.  und  P.,  1889,  vi.,  p.  451). 

3  Fenoglio,  "  Enterocolite  par  Amoeba  coli  "  (Arch.  ital.  d.  med.,  1890,  xiv.,  p.  62). 

••  Councilman  and   Lafleur,    "  Amoebic  Dysentery  "  (Johns   Hopk.   Hasp.   Ref>.,    ii., 
P-  395)- 

5  Dock,  "  Observations  on  Amoeba  coli  in  Dysentery,"  (Daniels'  Texas  Med.  Journ., 
1891,  p.  419). 

Kruse,  W.,  and  Pasquale,  "  Unters.  ub.  Dys."  (Ztschr.  f.  Hyg.,  1894,  xvi.,  p.  i). 
Zunker,  "  Ueb.  d.  York.  v.  Cere.  int.  im.  Dig.  d.  Mensch."       (Dtsch.  Ztschr.   f.  pr. 
Med.,  1878,  p.  i). 

Quincke  and  Roos,  "  Ueb.  Amceb.-Enter."  (Berl.  kl.  Wchschr.,  1893,  p.   1089). 
Roos,  E.    "  Ueb.  Infus.-Diarrhoe  "  (Dtsch.  Arch.  f.  kl.  Med.,  1893,  li.,  p.  505). 
*  Kannenberg,   "  Ueb.  Infus.  im  Sputum1'  (Vir chow's  Arch.  f.  path.  Anat.,   1879, 
Ixxv.,  p.  471  ;    Ztschr.  f.  kl.  Med.,  1880,  i.,  p.  228). 

11  Streng,  W.,  "  Infus.  i.  Sput.  bei  Lungengansran  "  (Fortschr.  der  Med.,   1892,  x., 
P-  757)- 

12  Artanlt,  St.,  "  Flore  et  faune  d.  cav.  pul."  (Arch,  de  paras.,  1898,  i.,  p.  278). 

13  Litten,  "  Ueb.  Hydropneumothorax  "  (Verh.  d.  Congr.  f.  inn.  Med.,  1886,  p.  417). 

14  Roos,  E.,  "  Ueb.  Infus.-Diarrhoe  "  (Dtsch.  Arch.  /.  kl.  Med.,  1893,  li.,  p.  505). 

15  Perroncito,  E.,  "  Ueb.  d.  Art  d.  Verbreitg.  d.  Cere,  infest."  (C.  f.  B.  u.  P.,  1888,  iv., 
p.  220  ;  Arch.  ital.  d.  biol.,  1888,  x.,  p.  257  ;  Ann.  R.  Ace.  d'agric.,  Torino,  1889,  xxxii.). 

16  Piccardi,   "  Ale.  prot.  d.  fed  dell'  uomo  "  (Giorn.  R.  Ace.  d.  med.,  Torino,  1895, 
Iviii.,  i  ;    Progr.  med.,  1895,  p.  377) 


54 


THE    ANIMAL    PARASITES    OF    MAN 


FIG.  14. — 


2.  Monas  pyophila,  R.  Blanch,  1895. 

R.  Blanchard  *  thus  designates  a  Flagellate  •  that  Grimm  * 
found  in  the  sputum,  as  well  as  in  the  pus  of  a  pulmonary 
and  hepatic  abscess,  in  the  case  of  a  Japanese 
woman  living  in  Sapporo.  The  parasites  resemble 
large  spermatozoa.  The  body,  measuring  0^030 — 
O'o6o  mm.,  has  the  shape  of  a  heart  or  a  myrtle  leaf, 
and  is  surrounded  by  a  thick  cuticle  which  is  sup- 
posed to  continue  in  the  interior  of  the  body, 
dividing  it  into  three  parts.  There  is  a  long  ap- 
pendix at  the  rounded  pole  covered  over  its  greatest 
extent  by  the  cuticle  ;  the  extremity,  however, 
is  free  and  resembles  a  flagellum.  The  parasites 
were  very  agile,  frequently  changed  their  shape,  and 
were  able  to  retract  the  long  appendix  within  the 
Monas  pyophila,  body,  which  then  assumed  a  round  form. 

R.  Blanch,  (after 
Grimm). 

3. — Cercomonades  in  the  urine. 

As  far  back  as  1859  Hassall3  described  a  flagellated  infu- 
sorium which  he  called  Bodo  urinarius.  It  was  found  in  alka- 
line urine  a  short  time  after  exposure  to  the  air.  About  fifty 
samples  of  urine  from  different  persons  were  collected  and 
specimens  exposed  to  the  air,  and  the  results  proved  decisively 
that  Bodo  urinarius  had  only  settled  in  the  urine  subsequently. 
This  communication  would  not  have  been  included  here  had  not 
Kiinstler4  in  1883  announced  the  occurrence  of  a  flagellate 
designated  Bodo  urinarius  in  the  freshly  passed  urine  of  a  patient,, 
and  at  once  conveyed  the  impression  that  it  was  a  parasite  origi- 
nating from  the  urinary  passages.  This  form  has  been  variously 
criticised.  Blanchard5  sets  it  up  as  a  distinct  parasite,  and,  as 
he  considers  that  it  differs  from  Bodo  urinarius,  Hass,  he  calls 
it  Cystomonas  urinaria.  However,  as  the  generic  name  of 
Plagiomonas  already  existed  for  Protomonadines  with  two  flagella 

1  Blanchard,  R.,  "Malar.  Paras.,  <5-c.,"  1895,  p.  690. 

2  Grimm,  F.,  "  Ueb.  ein.  Leber-  u.  Lungenabsc.  mit  Protoz."  (Arch.    /.  Chir.,   1894, 
xlviii.,  p.  478). 

3  Hassall,  "  On  the  Development  and    Significance  of   Vibriolineola,  Bodo  urinarius 
.     .     .     in  Alkaline  and  Albuminous  Urine  "   (The  Lancet,   1859,  ii.,  p.   503). 

4  Kiinstler,  "  Analyse  micr.  des  urines  d'un  malade    atteint  de  pyeMte  chron.  consec. 
a  une  oper.  de  faille  "  (Bull.  soc.  d'an.  et  de  phys.  norm,  et  path.,  Bordeaux,   1883,  iv,, 
p.  215). 

5  Blanchard,  R.,  Traite  de  Zool.  med.,  Paris,  1885,  i.,  p.  78. 


CERCOMONADES    IN    THE    URINE 


55 


at    the    anterior    extremity,      I !  suggested     the     denomination    of 
Plagiomonas  urinaria.     Blanchard  regarded  Trichomonas  irregular  is, 
Slsb.,    as   synonymous,    and    in    accordance   with    this  opinion    he 
recently2     named    the    species    Plagiomonas     irregu- 
lar is    (  =  Bo  do  urinarius,    Kunstl.  nee    Hass).      This 
at    the   time    and   even  now  does  not  appear  to  me 
to  be  justified,  as  Salisbury 3  found  Trichomonas  irre- 
gularis  not  only  in  the  urine,  but  also  in  the  vagina 
of  the  same  person,  and  therefore  a  confusion   with 
Trichomonas  vaginalis    is    quite    possible.      On     the 
other    hand,    Th.    Barrois4  considers    Hassall's   and 
Kiinstler's   Bodo   urinarius   to   be   identical,    and  the 
latter  not  a  parasite  of  man.    He  bases  this  opinion 
on  his  own  experience.      In  the  freshly-passed  urine 
of  a  patient,  a   physician    in    Lille  found  a   number 
of  flagellates,    and  Barrois  confirmed  their  presence  ; 
however,   as  the    urine    was  opaque,  had  an  alkaline 
reaction,    and    contained    innumerable    and    various 
bacteria  in  addition  to  the  flagellates,  Barrois  doubted 
the   freshness  of  the  material  ;    when,    subsequently, 
the    urine  of    the  same    patient    was    examined    im- 
mediately   after  evacuation,    no    trace    of  flagellates 
could  be  found  ;   of  course  the  urine  first  examined 
had  not  stood  long,  so  that  it  must 
be    conjectured  that   the  germs  of 
the    flagellates    were    only   present 
periodically    in  the    atmosphere  of 
the  sick  room.      At  all  events  this 
observation  demonstrates  how  care- 
ful one   must  be  in   the   judgment 
of  flagellates  appearing  in  the  secre- 
tions and  excretions  of  man. 

As,  moreover,  decomposition  had 
set  in  in  the  urine  examined  by 
Kiinstler,  and  numbers  of  various 
bacteria  were  present  in  addition 
to  the  flagellates,  Barrois  does  not 


FIG.  15. — Bodo 
urinarius,  Kstlr. 
(after  Kiinstler). 


FIG.  1 6. — Flagellata  observed  by 
Barrois  in  the  urine  of  a  man  (after 
Barrois). 


1  Braun,  M.,  Die  thier.  Par.  d.  Mensch.,  2nd  edition,  1895,  P-  Io8- 

2  Blanchard,  R.,  Mai.  paras.     .     .     .     Paris,  1895,  p.  691. 

3  Salisbury,    "  On  the  Parasitic  Forms  developed  in  Epithelial   Cells  of   the    Urine 
and  Genital  Organs  "  (Amer.  Journ.  med.  sc.,  1868.) 

4  Barrois,  Th.,  "  Quelq.  obs.  au  sujet  du  B.  urin."    (Kev.  biol.  nord.  France,  1894-95, 
vii.,  p.  165). 


56  THE    ANIMAL    PARASITES    OF    MAN 

consider  that  this  case  either  is  convincing.  As  a  matter  of  course 
the  appearance  of  cercomonades  in  the  urine  of  man  cannot  be  dis- 
puted, but  hitherto  no  proof  has  been  adduced  to  show  that  they 
live  in  man. 


4. — Trypanosoma,  Gruby,  1843. 

Since  the  'forties  we  have-  known  through  Valentin,  Gluge, 
Remak,  &c.,  of  flagellates  in  the  blood  of  fishes  and  amphibia,  and 
soon  afterwards  these  parasites  were  found  in  the  blood  of  rats 
and  marmots.  The  species  living  in  European  frogs  was  called 
Trypanosoma  sanguinis  by  Gruby.1 

At  the  present  date  we  distinguish  a  larger  number  of  species 
which  live,  some  of  them,  in  the  blood  of  various  vertebrates, 
and  some  of  them  in  the  intestine  of  vertebrate  and  invertebrate 
animals.  A  few  forms  have  acquired  great  importance  from  the 

(a)  '(b) 


FIG.  17. — Trypanosoma  Lewisi,  Kent. 
From  the  blood  of  a  rat  ;  O'OoS-o'Oio  mm. 
in  length  ;  (a)  fresh  ;  (b)  preserved  ;  the 
nucleus  is  at  the  flagellated  end.  (After 
Kempner  and  Rabinowitch.) 


fact  that  they  cause  more  or  less  serious  diseases  in  domestic 
animals,  and  that  their  presence  not  only  endangers  the  lives  of 
the  latter,  but  frequently  decimates  them.  Thus  Trypanosoma 
brucei,  Plimm  and  Bradf.,  is  known  to  be  the  cause  of  the  dreaded 
Tsetse  fly  disease  (nagana),  occurring  in  various  parts  of  Africa  ; 
T.  evansi  (Steel)  induces  the  disease  known  as  surra,  which 
occurs  in  Southern  Asia ;  while  T.  equiperdum,  Dofl.,  plays  a 
part  in  dourine,  a  disease  observed  in  N.  Africa,  the  south  of 
France,  and  Spain. 

According  to  a  report  from  Nepveu,2  trypanosomes  also  occur 
in  the  blood  of  man,  but  this  seemed  doubtful,  as  the  observa- 
tions were  made  in  Algiers  in  patients  suffering  from  malaria,  and 
it  was  not  unreasonable  to  surmise  that  developmental  stages  of 


1  Gruby,  "  Sur  une  nouv.  esp.  d'hematoz."     (C.  R.  Ac.,  Paris,  1843,  xvii.,  p.  1134;' 
Ann.  sc.  nat.  zool.,  1844,  i->  P-  104). 

3  Nepveu,  C.  R.,  soc.  bioL,  Paris,  1898  (10),  p.  1172. 


TRYPANOSOMA 


57 


malarial    parasites    had 


FIG.  1 8. — Trypanosoma  car- 
assii,  Mitr.  From  the  blood  of 
the  crusian  (Carassius  vulgaris), 
drawn  with  a  blood  corpuscle 
from  the  host  for  comparison 
of  size.  (After  Mitrophanow.) 


been  mistaken  for  trypanosomes.  The 
statement  has,  however,  acquired  new 
importance  from  the  fact  that  Button1 
has  observed  trypanosomes  in  the  blood 
of  a  European. 

Trypanosomes  are  flagellates  of 
elongated  shapfc,  which,  nevertheless, 
are  capable  of  changing  their  form. 
They  bear  an  undulating  membrane  on 
one  side  along  the  entire  length  of  the 
body,  and  in  most  cases  possess  a  fla- 
gellum  at  one  extremity. 

Transmission  is  effected  in  the  same 
species  by  blood-sucking  arthropoda  ;  T. 
brucei  is  conveyed  by  the  tsetse  fly 
(Glossina  morsitans),  T.  lewisi  by  fleas  ; 
the  carrier,  however,  for  most  species 
is  still  unknown.2 


Trypanosoma. 

The  discovery  of  a  trypanosome  in  sleeping  sickness,  by  Dr. 
Aldo  Castellani,  in  1902,  has  given  great  pathological  importance 
to  the  genus  Trypanosoma.  It  is  therefore  necessary  to  supple- 
ment the  author's  brief  mention  of  this  group  of  parasites  with  a 
summary  of  the  most  recent  information  on  the  subject. 

Trypanosomes,  as  usually  seen  in  the  blood  of  man  and  cattle, 
are  elongated,  unicellular  bodies  provided  with  a  kind  of  fin-fold, 
the  undulating  membrane,  which  runs  along  the  dorsal  edge  of  the 
body,  forming  frill-like  folds,  and  terminates  in  a  free  whip-like 
filament,  the  flagellum,  which  may  vary  greatly  in  length. 
Stained  specimens  show  very  clearly  a  large  nucleus,  usually  about 
the  middle  of  the  body,  and  a  much  smaller  chromatin  mass 
placed  more  or  less  near  one  pole.  This  small  mass  of  chromatin 
has  been,  variously  termed  blepharoplast,  micro-nucleus,  centrosome. 
I  will  use  the  term  blepharoplast  as  the  most  appropriate.  In 
fact,  it  is  from  this  small  chromatin  mass  that  arises  the  flagellum. 
The  extremity  of  the  body  which  encloses  the  blepharoplast  is  the 
anterior  extremity ;  it  varies  greatly  in  shape  at  different  stages  of 

1  Laveran,  A.,  and  Mesnil,  F.,  "  Du  mal.  d  trypanos.  leur  repart.  d  la  surface  du  globe  " 
(Janus,  1902,  vii.). 

'  ;  -  Other  species  of  Glossina  besides  Glossina  morsitans  carry  Trypanosoma  brucei. 
Sleeping  sickness  (Trypanosoma  gambiense)  is  carried  by  Glossina  palpalis.  Surra 
must  be  carried  by  some  other  biting  flies,  as  Glossinae  do  not  occur  in  Asia.  (F.V.S.). 


58  THE   ANIMAL   PARASITES   OF   MAN 

development ;  it  may  be  pointed  or  obtuse.  The  opposite  end  is 
the  posterior  extremity ;  it  always  tapers  to  a  point  and  is  con- 
tinued by  the  free  end  of  the  flagellum.  Most  authors  call  the 
posterior  extremity  anterior,  because,  as  a  rule,  trypanosomes  move 
more  rapidly  and,  apparently,  more  frequently  with  this  end 
foremost ;  but  the  direction  of  locomotion  is  not  a  good  argument , 
otherwise  we  should  have  to  call  the  posterior  extremity  the  well- 
developed  head  of  Cephalopods,  simply  because  these  animals  move 
more  rapidly  with  the  tail  end  foremost,  and  thus  escape  the 
animals  that  prey  upon  them.  A  comparative  examination  of 
the  flagellates,  and  especially  of  the  free-living  forms,  shows  very 
clearly  that  the  true  anterior  extremity  is  that  from  which  the 
flagellum  arises.  In  most  genera  the  flagellum  is  not  only  an. 
organ  of  locomotion,  but  also  an  important  means  for  the  capture 
of  food.  In  such  forms  as  Euglena  the  anterior  extremity  is 
provided  with  an  oral  cavity  which  opens  at  the  base  of  the 
flagellum.  In  Euglena  the  flagellum  is  entirely  free  and  sways 
in  front  of  the  head  of  the  creature,  like  a  proboscis,  and,  indeed, 
it  was  called  proboscis  by  Ehrenberg.  In  trypanosoma,  the 
flagellum  bends  directly  backwards  and  is  attached,  for  a  con- 
siderable portion  of  its  length,  to  the  body  by  a  thin  web  of 
body  plasma.  The  flagellum  is  composed  of  chromatin.  In  cer- 
tain stages  it  is  cast  off.  It  is  easily  reproduced  by  the  blepharo- 
plast.  When  cast  it  may  continue  to  move  independently  for 
some  time.  Adjoining  or  surrounding  the  blepharoplast  is  a  clear 
area  called  the  vacuole ;  it  probably  represents  the  contractile 
vesicle  of  other  flagellata.  Sometimes  the  plasma  of  stained  speci- 
mens is  beset  with  a  variable  number  of  dark-staining  granules ; 
these  granules  represent  reserve  material  and  are  called  chromato- 
phores. 

By  examining  large  numbers  of  trypanosomes  during  the  course 
of  a  trypanosoma  infection,  one  soon  notices  that  the  parasites 
vary  considerably  in  size  and  shape.  A  more  careful  study 
enables  us  to  group  these  various  forms  into  three  distinct  types ,. 
corresponding  to  the  well-known  forms  of  the  H ' cemamcebidce  found 
in  the  blood  of  malaria  patients. 

The  most  frequent  form  is  the  asexual  form,  which  multiplies 
very  rapidly  by  simple  longitudinal  division.  It  is  usually  seen 
in  the  process  of  division.  This  process  begins  most  frequently 
with  the  division  of  the  blepharoplast,  which  elongates  and  then 
divides.  The  nucleus  divides  almost  simultaneously,  sometimes 
before  the  blepharoplast.  The  division  of  the  blepharoplast  brings 


TRYPANOSOMA  59 

about  the  division  of  the  flagellum,  and  the  division  of  the 
flagellum  is  followed  by  the  division  of  the  whole  body.  The 
duplication  of  the  flagellum  begins  at  the  point  of  origin  and 
terminates  at  the  free  end ;  the  duplication  of  the  body  proceeds 
dorso-ventrally,  but  the  division  forms  do  not  separate  along  the 
ventral  border  until  the  newly-formed  flagellum  has  entirely  parted 
from  the  old  one,  thus  the  separation  of  the  division  forms  pro- 
ceeds from  the  tail  end  forwards.  One  frequently  sees  parasites 
still  adhering  by  their  anterior  extremities.  The  division  forms 
are  of  about  equal  size  and  slightly  smaller  than  the  parent  form. 
Amongst  these  asexual  forms  we  occasionally  find  some  larger 
forms  which  are  analogous  to  the  macrogametes  of  the  malaria 
parasites  ;  as  a  rule,  these  forms  do  not  divide  until  after  copu- 
lation, which  probably  in  most  species  takes  place  in  the  body  of 
an  alternative  host.  They  are  characterised  by  a  larger  size, 
which  may  be  more  than  double  that  of  the  asexual  forms,  by 
a  stumpy  shape,  by  a  short  flagellum  and  by  the  presence  of 
numerous  chromatophores.  Sometimes  vacuoles  are  found  in  the 
plasma  of  these  forms.  They  end  by  becoming  almost  round  and 
losing  entirely  their  flagellum.  By  the  side  of  these  female 
forms  we  meet  some  very  slender  hyaline  forms  with  very  long 
flagellum,  with  comparatively  large  nucleus  and  large  blepharo- 
plast.  They  are  the  male  forms  or  microgametes.  The  number 
of  the  sexual  forms  varies  greatly  in  different  slides.  At  times 
they  are  quite  numerous. 

The  life-history  of  the  trypanosomes  is  very  superficially 
known.  Quite  recently  Dr.  Fritz  Schaudinn  has  studied  the 
entire  life  cycle  of  Trypanosoma  noctuce,  a  trypanosome  of  the 
little  owl  (Athence  noctuce),  the  gametes  of  which  were  described 
in  1891  by  Celli  and  Sanfelice  under  the  name  of  Hcemoproteus 
(=  Halteridium)  noctuce.  I  will  give  a  brief  sketch  of  the  life- 
history  of  Trypanosoma  noctuce  as  a  guide  to  the  study  of  the 
bionomics^  of  other  species.  Trypanosoma  (=  Halteridium)  noctuce, 
like  Hcemamceba  relicta  (Proteosoma),  insures  the  continuancy  of  its 
existence  by  an  alternation  of  generative  processes  and  by  a 
change  of  hosts.  Its  intermediary  host  is  the  little  owl  (Athence 
noctuce),  its  definitive  host  is  Culex  pipiens. 

When  first  introduced  into  the  blood  of  the  bird,  the  para- 
sites have  the  form  of  trypanosomes,  but  they  are  as  a  rule  very 
small.  They  attach  themselves  to  the  erythrocytes,  discard  their 
flagella  and  assume  the  well-known  halteridium  form.  After  about 
twenty-four  hours,  granules  of  pigment  begin  to  appear  in  their 


60  THE  ANIMAL  PARASITES  OF  MAN 

plasma.  The  period  of  growth  lasts  six  days,  but  the  parasite 
does  not  remain  attached  to  the  erythrocyte  the  whole  time  ;  as 
a  rule  it  leaves  the  corpuscle  at  night,  assumes  the  trypanosoma 
form  and  moves  about  freely  in  the  plasm  until  the  next  morning, 
when  again  it  attaches  itself  to  a  red  blood  corpuscle  in  order  to 
absorb  nutriment.  These  alternating  periods  of  movement  and 
rest  follow  one  another  until  full  growth  is  attained.  Then  a 
multiplication  stage  sets  in  and  the  parasites  multiply  by  con- 
secutive longitudinal  divisions  until  the  products  of  division  have 
attained  a  minimum  size.  The  small  flagellates  then  attach 
themselves  once  more  to  the  erythrocytes,  and  the  alternating 
stages  of  growth  and  multiplication  continue  until  the  blood 
literally  swarms  with  parasites. 

By  examining  the  blood  of  the  owl  one  sees  the  asexual  forms 
of  different  sizes  and  in  different  stages  of  division,  but  one  dis- 
tinguishes also  other  forms  with  coarsely  granular  plasma  and 
fine  pigment,  which  contain  a  small  nucleus  adjacent  to  the 
blepharoplast,  likewise  quite  small.  These  forms  are  the  macro- 
gametes,  they  penetrate  the  erythrocytes  and  grow  more  gradually, 
accumulating  more  and  more  reserve  material  in  their  plasma. 
They  appear  to  change  their  host  cells  more  rarely,  and  towards 
the  end  of  their  growth  are  no  longer  able  to  assume  the  form 
of  trypanosomes.  The  mature  macrogametes  are  quite  unable  to 
leave  their  host  cells,  and  are  found  surrounded  by  a  pale  residue 
of  the  erythrocyte,  the  nucleus  of  which  is  then  situated  quite  at 
the  periphery. 

The  macrogametes  are  the  only  forms  which  persist  at  the  end 
of  the  acute  stage  of  the  halteridium  disease,  and  after  long 
intervals  they  are  capable  of  bringing  about  a  relapse  by  repro- 
ducing parthenogenetically  the  asexual  forms.  The  macrogametes 
arise  from  the  asexual  forms,  and  can  be  recognised  even  in  their 
earliest  stages.  The  fertilisation  of  the  macrogametes  takes  place 
at  the  moment  in  which  the  parasites  leave  their  intermediary 
host. 

The  microgametocytes  also  arise  from  the  asexual  forms,  and 
their  nature  may  likewise  be  recognised  in  the  earliest  stages. 
They  are  characterised  by  pale  plasma,  coarse  pigment,  large 
nucleus,  large  blepharoplast.  The  mature  microgametocytes  give 
rise  to  eight  microgametes  which  develop  as  soon  as  the  blood  is 
abstracted,  but  invariably  perish  within  their  mother  cells  when 
left  in  the  circulatory  system  of  the  bird.  As  soon  as  the  macro- 
gamete  makes  its  exit  from  the  avian  host  it  becomes  globular, 


TRYPANOSOMA  6l 

bursts  out  of  the  remains  of  the  enclosing  erythrocyte,  and  under- 
goes a  series  of  nuclear  changes  preparatory  to  fertilisation.     Then 
a   microgamete   penetrates   the   macrogamete,    aided    by   a   cone   of 
attraction  which  is    produced    on  the  latter  at  the  spot  where  the 
female  nucleus  lies.     The  macrogamete  thus  becomes  the  ookinet,  it 
assumes  an  elongated  form  and  becomes  motile.      When  the  blood 
begins  to  separate  within  the  midgut  of  the  mosquito,  the  ookinets 
migrate  towards  the  anterior  portion  and  here  give  rise  to  trypano- 
soma    forms,    both   sexual   and   asexual.      The   asexual    and    female 
forms    multiply    by   longitudinal    division    as    in    the    blood    of   the 
bird,    the    male    forms    by    multiple    division.      The    small    division 
forms   attach   themselves   to   the   epithelial   cells   of   the   midgut  by 
means   of    their    flagella,    which    become    short    clinging    structures. 
The   attachment  of  the  parasites  coincides  with  the  end  of  diges- 
tion when  the  midgut  remains  empty.      Should  the  mosquito  feed 
a   second   time,   the   parasites   again   become   motile.     Some   of   the 
resting  parasites  penetrate  between  the  cells  or  even  between  the 
cells    and    the    tunica    elastico-muscularis .      Usually    in    these    situa- 
tions they  become  globular  and  their  flagella  disappear  altogether. 
When  the  latter  forms  again  become  free,  they  develop  once  more 
their    flagella    from    the    blepharoplasts.      The    female    forms    may 
grow    to    about    three    times    the    size    of    the    asexual    ones    and 
become  laden  with  reserve  material.     They  seem  unable  to  multiply 
by    longitudinal    division    and    can    only    accomplish    sluggish    con- 
traction movements.      They  are  no  longer  capable  of  transforming 
themselves  into  trypanosomes.      These  gregarine-like   resting  forms 
of  female  trypanosomes  have  a  remarkable  power  of  withstanding 
adverse    conditions.      When    the    mosquitoes    after    the    first    meal 
are  obliged  to  fast  for  a  long  period,  the   asexual  and  male  forms 
die   off,    but   the   female   forms   persist,    they   lie   between   the   epi- 
thelium and  the  tunica  elastico-muscularis,  and  greatly  resemble  the 
zygotes  of  malaria  parasites,   although  lacking  in   pigment.  f  These 
forms  lose  entirely  their  flagellum,   the  blepharoplast  lies  close  to 
the  nucleus,   the  reserve  material  is  gradually  used  up,   and  large 
vacuoles  appear  in  the  plasma.     If,  after  a  long  fast,  the  mosquito 
again  feeds,   the  female  forms  which  have  survived  reproduce  the 
asexual  forms  by  parthenogenesis  (a  kind  of  auto-fertilisation). 

The  zygotes  which  give  rise  to  male  forms  are  somewhat 
smaller  than  those  which  develop  into  female  forms,  their  plasma 
is  almost  hyaline  and  coarsely  vacuolar,  the  nucleus  is  relatively 
larger,  and  is  very  rich  in  chromatin.  Having  undergone  certain 
nuclear  changes  the  microgametocyte  becomes  globular  and  breaks 


62  THE    ANIMAL    PARASITES    OF    MAN 

up  into  eight  small  trypanosomes.  These  microgametes  are  dis- 
tinguished from  the  other  forms  not  only  by  their  diminutive  size, 
but  by  the  development  of  their  locomotor  apparatus.  They  have 
large  blepharoplasts  and  very  long  flagella,  which  render  them 
exceedingly  motile. 

When  the  blood  has  been  entirely  digested  and  the  midgut 
remains  empty,  the  parasites  attach  themselves  to  the  epithelial 
cells  lining  the  posterior  part  of  the  stomach  about  the  valve  in 
front  of  the  malpighian  tubes.  Here  they  agglomerate  in  large 
clusters.  When  very  numerous  the  parasites  may  greatly  injure 
the  walls  of  the  midgut  and  thus  cause  the  death  of  the  mosquito. 
If  the  infection  is  followed  by  a  long  fast,  all  the  asexual  and 
male  forms  die  oif,  the  female  forms  alone  persisting.  When  the 
mosquito  again  sucks  blood  the  parasites  detach  themselves,  dis- 
tribute themselves  in  the  blood,  and  then  pass  into  the  narrow 
anterior  portion  of  the  midgut,  where  they  form  a  large  cluster. 
At  the  time  of  the  next  feed  the  whole  cluster  is  pushed  back  by 
the  inrushing  blood  right  through  the  midgut  into  the  ileum, 
thence,  by  the  peristaltic  contractions  of  the  intestine,  the  cluster 
is  passed  into  the  colon  as  far  as  Basili's  curvature,  the  narrowest 
section  of  the  intestine.  On  account  of  the  nature  of  the  epithe- 
lium in  this  part,  the  parasites  are  able  to  penetrate  through  the 
intestinal  wall.  Thus  they  reach  the  circulation,  and  through  the 
dorsal  vessel  some  are  carried  forwards  into  the  lacunoma  round 
the  pumping  organ,  others  are  carried  to  the  ovaries.  Those 
carried  forwards  come  to  rest  between  the  pumping  organ 
and  the  pharyngeal  valve  ;  here  they  form  a  thick  cluster,  and 
by  injuring  the  tunica  elastico-muscularis,  which  is  very  delicate 
at  this  part,  they  pass  into  the  pharynx.  They  are  thence  passed 
into  the  blood  of  the  alternative  host  during  the  evacuation  of 
the  sucking  reservoirs.  The  entire  period  of  the  migration  of  the 
parasites  from  their  entry  into  the  body  of  the  mosquito  to  their 
exit  from  the  latter,  occupies  a  period  of  from  seven  to  eight  days. 

The  parasites  that  attain  the  ovaries  penetrate  the  youngest 
eggs,  and  the  macrogametes  go  to  rest  within  the  vitellus.  The 
latter  remain  in  the  gregarine  condition  during  the  entire  develop- 
ment of  the  embryo.  They  subsequently  pass  into  the  larva,  and 
are  found  also  in  the  perfect  insect.  The  mosquito  recently 
emerged  from  its  pupa  case  does  not  seem  able  to  transmit  the 
infection  by  means  of  its  first  bite.  According  to  Schaudinn's 
observations  it  can  infect  birds  only  at  the  time  of  its  third  feed. 


GREGARINIDA  63 

Class  III.     Sporozoa. 

Since  the  year  1879  a  number  of  isolated  uni-cellular  parasites  that 
produce  spores  covered  with  shells  are,  according  to  R.  Leuckart,  included 
with  the  gregarines,  and  this  large  group  of  protozoa  is  termed  Sporozoa. 
The  Sporozoa  comprise  the  so-called  psorosperm  tubes  (J.  Miiller),  i.e., 
Myxosporidia,  Butschli ;  the  oval  or  round  Psorospermia  (Eimer),  i.e.,  Coccidia, 
Lkt.,  and  Rainey's,  or  Miescher's  tubes,  i.e.,  Sarcosporidia,  Biitschl.  Later 
the  Microsporidia  and  the  Hcsmosporidia  were  also  classed  with  the  Sporozoa. 

Order   i.     Gregarinida. 

Although  hitherto  the  gregarinida  have  not  been  observed  either  in  human 
beings  or  .vertebrate  animals,  they  must  not  be  entirely  omitted  here, 
because  they  belong  to  the  oldest  known  sporozoa,  and  our  knowledge  of 
them  at  the  present  time  is  less  complete — at  any  rate,  in  regard  to  the 
history  of  development — than  that  o-f  other  groups  (Coccidia,  H&mosporidia). 

Their  bodies,  which  are  usually  elongated  and  frequently  tape-like,  and 
the  length  of  which  varies  according  to  the  species  between  o-oi-i6  mm., 
may  consist  of  a  single  cell,  as  in  the  Monocystidea,  inhabiting  the  body 
cavity  of  echinodermata,  annelida,  &c.,  or  may  be  divided  into  two  or  three 
consecutive  sections  (Polycystidea,  which  invade  the  intestine,  particularly  of 
arthropoda). 


FIG.    19. — Monocystis   a^ilis,  St.     From   the   vesicula 

seminalis  of    earthworms;      250/1    (After,    v.    Stein). 

(a)  Quiescent  ;    (6)  moving. 


The  most  anterior  section,  epimerit,  is  a  variously-shaped  %  organ  that  is 
used  by  the  parasite  to  cling  to  the  intestinal  epithelial  cells  of  its  host  ; 
it  is  generally  sunk  within  or  between  the  cells,  and  when  this  condition 
(cephalin,  cephalont)  is  given  up  the  epimerite  is  cast  off,  tricystic  forms 
thereby  becoming  dicystic.  The  next  section,  protomerit,  is  separated 
from  the  principal  section,  the  deutomerite,  by  an  ectoplasmatic  transverse 
partition  ;  the  large  vesicular  nucleus  (figs.  20,  26),  which  is  provided  with  a 
usually  round  nucleolus  (caryosoma).  is  situated  in  the  deutomerit. 

The  surface  of  the  body  is  formed  by  a  hyaline  cuticle,  which,  however, 
is  not  always  so  stiff  as  to  prevent  changes  of  form  of  the  body.  Beneath 
the  cuticle  (fig.  21)  there  is  a  jelly-like  mass  that  plays  a  part  in  the 

1  Butschli,  O.,  "  Sporozoa  in  Bronn's  Cl.  it.  Ordn.  d.  Thierr.,  1882,  i.,  p.  479.  Balbiani, 
G.,  Lemons  sur  les  sporoz.,  Paris,  1884.  Wasielewski,  "  Sporozoenkunde,"  Jena,  1896. 
Labbe,  A.,  "Sporozoa,"  5th  Edition  of  "  Thierreichs,"  Berl.,  1899.  Hagenmiiller,  P., 
•"  Bibliographic  %in.  et  spec,  des  trav.  cone.  les.  Sporoz."  (Ann.  Mus.  hist.  nat.  Marseille, 
1899,  2,  i.,  Suppl.).  Liihe,  M.,  "  Erqebn.  d..neuer.  Sporozoenforsch.,  Jena,  1900. 


64 


THE    ANIMAL    PARASITES    OF    MAX 


gliding  movement  as  well  as  in  the  encystment.  The  thin  ectosarc  then 
follows,  and  this  also  forms  the  transverse  partition  between  the  protomerit 
and  deutomerit,  its  deepest  part  frequently  exhibiting  circular  rows  of 
muscles  (myophane,  myoneme)  on  both  sections.  The  principal  mass  of 
the  body  consists  of  the  very  granular  endosarc,  the  large  or  small,  and  usually 
round,  granules  being  composed  of  paraglycogen,  fats  and  other  materials. 
Some  of  the  gregarines  perform  peristaltic  or  worm-like  movements,  even 
in  the  mature  condition  (fig.  19),  others  glide  along  in 
the  contents  of  the  intestine  without  any  visible  change 
of  form — like  diatoms  in  water.  According  to  Schewiakoff ,' 
this  is  effected  by  the  secretion  of  a  slimy  matter  which 
soon,  stiffens  at  the  posterior  end  of  the  body,  adheres 
to  the  surface  on  which  the  creature  rests  and  propels 
it  forward.  It  is  likewise  this  secretion,  originating  from 
the  slime-secreting  layer,  which  enables  the  gregarines 
(clepsidrinidae)  living  free  in  the  intestine,  to  adhere  one 
to  the  other  in  rows. 

Propagation  of     the    gregarines    may    be    effected    in 

two  ways.  Sporula- 
My.  tion,  which  takes 
place  during  encyst- 
ment, has  long  been 
known.  Moreover  k 
at  all  events  in  a 
few  simpler  forms, 
the  so-called  schizo- 
gonia  may  take  place 
within  the  same  host, 
the  qntire  body  (after 
division  of  the  nu- 
cleus) separating  into 
several  nucleated 
segments  (merozo- 
ites),  each  one  of 
which  becomes  a 
gregarine  directly.2 

Sporulation  is  generally  brought  about  by  the  fusing  together  of  two  con- 
tiguous gregarines  and  their  consecutive  encystment  (fig.  22).  Encystment 
in  Ceratospora  is  said  to  be  omitted  or  may  be  confined  to  one  individual 
(as  in  Actinocephalus  dujardini}  ;  in  exceptional  cases  three  individuals  may 


FIG.  20.  —  Xiphor- 
hynchus  firmus. 
Leg.  With  the 
epimerit  fixed  in  an 
intestinal  epithelial 
cell ;  host  Dermestes 
lardarius;  enlarged. 
(After  Leger.) 


G.  E. 

FIG.  21. — Clepsidrina  munieri, 
Schneid.  ;  from  Chrysomela  hce- 
moptera.  Section  of  the  surface, 
1,500  times  enlarged.  (After 
Schewiakoff).  Cu.  =  Cuticle  ;  E. 
=  Ectosarc.  G.  =  Gelatinous 
layer.  My.  =  Myophane. 


1  Schewiakoff,  "  Ueb.  d.  Ursache  d.  fortschreit.  Beweg.   d.  Greear  "  (Z.  f.  w  Z     1804 
Iviii.,  p.  340). 

-  Cf.  Schneider,  A.,  " Ophryocystis  biitschlii"  (Arch.  Zool.  exp.,  1884,  2,  ii.,  p.  in  ; 
"  Ophr.  francesci"  (TabL  zool.,  1885,  i.,  p.  i).  Caullery  et  Mesnil.,  "  Sur  une  Greg, 
ccelom.  pre's.  dans  son  cycle  evolut.  une  phase  de  multipl.  asporulee  "  (C.  R.  Ac.  sc.,  Paris, 
1898,  cxxvi.,  p.  262  ;  C.  R.  soc.  biol.,  Paris,  1898,  v.,  p.  65).  Leger  et  Hagenmuller, 
Morph.  et  evolut.  de  I'Ophryoc.  schneideri"  (Arch.  Zool.  exp.,  1900,  3,  viii . ;  Notes 
No.  3).  Leger,  "  Nouv.  Sporoz.  des  law.  d.  Dipt."  (C.  R.  Ac.  sc.,  Paris,  1900,'  cxxxi., 
p.  722.)  Caullery  and  Mesnil,  "  Parasit.  intracell.  et  la  multi-blic.  asexuec  d  ere*  "  (C  R 
soc.  biol,  Paris,  1901,  liii.,  p.  84). 


GREGARINIDA 


be:  encysted  together,  and  in  one  species  (Pyxinia  jrenzeli}  this  is  as  frequent 
as  the  encystment  of  two.1 

The  fusion  is  effected  with  synonymous  layers,  thus  being  different 
from  the  above-mentioned  association  (adherence),  which  can  always  be 
relinquished  or  broken  up. 

Hitherto  it  has  been  inferred  that  the  two  encysted  individuals  (sporonts) 
conjugate  because,  as  a  rule,  they  sooner  or  later  merge  into  one  another  ; 
this  opinion  is,  moreover,  supported  by  the  statements  of  Wolters 2  and 
Roboz,1  the  former  believing  that  he  has  actually  witnessed  the  fusion  of 
the  nuclei  of  the  two  encysted  individuals  that  sets  in  after  the  reduction 
of  the  nucleated  substance  and  the  expulsion  of  one  part,  whereas  the 
latter  has,  at  all  events,  observed  the  expulsion  of  portions  of  nucleus.  This 
latter  phenomenon  has  also  been  confirmed  by  recent  research4;  but,  on  the 
other  hand,  this  observation  has  by  no  means  proved  even  transient  union  of 
the  reduced  nuclei  of  the  two  sporonts,  and  accordingly  there  can  be  no 
question  of  the  conjugation  of  the  two  individuals  encysted  together  ;  their 
large  vesicular  nucleus  rather  dissolves,  the  greater  part  disappears  in  the 
substance  of  the  body,  or  is  sometimes  ejected,  and  a  new,  though  very  small, 
nucleus  is  formed  of  the  residue,  and  divides  mitotically.  The  daughter  nuclei 


FIG.   22. — Two  so-called  conjugation   stages  FIG.    23. — Sporulation    stage    of 

of  Clepsidrina  blattarum.      (After  Biitschli).  Clepsidrina      ovata,       schematised. 

(After  A.    Schneider.) 

divide  again — a  circumstance  we  have  long  been  acquainted  with — and  this 
process  is  repeated  until  a  large  number  of  nuclei  have  formed  in  each 
sporont,  which  at  the  commencement  of  this  process  rounded  off  and  encysted 
themselves.  Sooner  or  later,  the  cuticle  surrounding  the  two  encysted  parasites 
dissolves,  and  the  nuclei  crowd  to  the  periphery  of  the  united  masses  of 


1  Laveran  et  Mesnil,   "  Sur  quel.  particul.   de  I'evot.  d'une  greg."   (C.  R.  soc.  biol., 
Paris,  1900,  lii..  p.  554). 

2  Wolters,  M.,  "  Die  Conj'ug.  u.  Sporenbildung  bci  Greg."  (Arch.  f.  mikr.  An.,  1891, 
xxxvii.,  p.  99). 

3  Math.  Ber.  aus  Ungarn.,  1887,  iv.,  p.  146  ;  andjourn.  R.  Micr.  Soc.,  London,  1887, 
p.  769. 

4  Cuenot,  S.,  "  Evolut.  d.  greg.  ccelom.  du  Grillon  dom." _(C.  R.  Ac.  sc.,  Paris,  1897, 
cxxv.,  p.  52)  ;    "  Sur  la  pret.  con-fug,  d.  Greg."  (Bibl.  Anai.,  1899,  p.  70)  ;    "  Rech.  sur 
I'evol.  d.  Greg."  (Arch,  de  biol.,  1901,  xvii.,  p.  581).     Siedlecki,  M.,  "  Geschl.   Vermehr. 
d.  Monoceptis  ascidice  "  (Bull,  intern,  de  I' Ac.  d.  sc.  d.  Cracovie,  1899.  P-  5T  5  V    Mrazek,  A., 
"  Studia  o  sporozoich  "  (Vestn.  Krai.  Ceske  spolecnosti  nduk,  1899). 

S 


66 


THE    ANIMAL    PARASITES    OF    MAN 


protoplasm.  A  small  portion  of  the  protoplasm  gal  hers  round  each 
nucleus,  and  a  number  of  small  cells,  hitherto  called  sporoblasts,  are 
formed  (fig.  23)  on  a  large  unused  residue  of  protoplasm  (residual  body, 
sporophor).  As,  however,  these  formations  coalesce  in  pairs,  as  has  been 
discovered  by  Siedlecki  and  Cuenot,  they  must  be  called  gametes.  They 


FIG.  24. — Monocystis  sp.  from  the  vesicula  seminalis 
of  earth-worms  14001.  (a)  Spore  with  spore  cuticle 
developed  ;  (b)  mature  spore  with  sporozoits  and 
residual  bodies  ;  (c)  optical  transerve  section  of  mature 
spore  (after  Biitschli). 


appear  to  be  completely  alike,  but  it  is  very  probable  that  each  one  of  the 
couple  is  the  product  of  one  of  the  sporonts  ;  in  accordance  herewith  the  con- 
jugation or  copulation  would  be  isogamous.1  The  designation  sporoblast 
hitherto  in  use  may  be  applied  to  the  product  of  amalgamation.  They  are 
transformed  into  spores,  assuming  a  more  fusiform  shape,  and  they  secrete  a 
covering  of  the  same  shape,  within  which  the  enclosed  cells,  after  repeated 
mitotic  division  of  the  nucleus,  divide  -up  into  a  certain  number  (usually 


a. 


d. 


FIG.  25. — Spores  of  various  gregarines.     (a)  of  Porcspora  •   (b)  of  Xi\. 
of  AncyroQhora  ;   (d)  of  Gonospo'ra  ;    (e)  of  Ceratospora.     (After  Leger. 


(b)  of  Xiphorhynchus  ; 


eight)  of  elongated  fusiform,  or  sickle-shaped  little  bodies,  the  sporozoites.  Even 
in  this  process  a  small  residual  body  remains,  around  which  the  sporozoites 
are  grouped  (fig.  24), 

The  development  of    a  covering  for   the  spores  is  lacking  in  Porospora  ; 


1  The  A  mphimixia  here  instanced  cannot,  however,  take  place  in  the  cases  in  which 
one  gregarine  alone  is  encysted.,  or  in  which  one  of  the  two  encysted  individuals  dies 
off,  and  the  other  then  sporulates  alone.  Accordingly  A  mp hi mixia  is  not  necessarily 
connected  with  the  conjugation  of  the  gametes. 


GREGARINIDA 


67 


which  is  also  the  only  genus  that  forms  more  than  eight  sporozoites 
fig.  25,  a).  The  form  and  size  of  the  spores  vary  considerably  according  to 
the  species,  and  afford  a  valuable  means  for  their  distinction  (figs.  25,  b-e). 

The  development  of  the  spores  within  the  cysts  generally  takes  place 
outside  the  host  in  the  open,  and  may  occupy  very  variable  times.  The 
cysts  discharge  their  contents — the  spores — either  by  simple  bursting  o/ 
the  envelope  of  the  cyst,  or  with  the  assistance  of  the  swelling  residual 
body,  or  by  means  of  particular  invertible  sporoducts,  one  or  several  of 
which  appear  on  the  envelope  of  the  cysts. 

The  ingestion  of  liberated  spores,  or  also  of  mature  cysts,  causes  infec- 
tion. The  sporozoites  are  actually  only  young  gregarines,  which  become 
free  through  the  bursting  of  the  spores,  acted  upon  by  the  intestinal  juice, 
and  in  many  cases  bore  into  the  epithelial  cells  of  the  invaded  intestine 
by  means  of  peculiar  movements,  which,  however,  are  not  amoeboid.1  In 


c. 


FIG.  26. — Development  of  Clepsidrina  longa.  (a)  Occupying  the  epithelial  cell ; 
(b,  c)  gradually  coming  out  ;  (d)  attached  by  the  clinging  apparatus ;  (e)  fully 
developed.  (After  Leger.) 


this  situation  they  increase  in  size,  and  grow  beyond  the  epithelial  cells 
occupied  by  them  ;  the  nucleus  then  lies  in  that  part  of  the  body  extend- 
ing from  the  cells  into  the  intestinal  lumen  ;  the  posterior  extremity  of 
the  parasite,  the  deutomerite,  is  then  separated  from  the  anterior  extremity 
by  a  transverse  partition,  and  this  part  is  finally  divided  into  the  epi- 
and  proto-merit  (fig.  26).  In  the  gregarines  inhabiting  the  abdominal  cavity 
an  intra-cellular  stage  is  wanting,  as  the  sporozoites,  which  have  become 
free  in  the  intestine,  travel  through  the  intestinal  epithelium  without 
staying  there  ;  but  a  few  species  inhabiting  the  intestine  depart  from  the 


1  The  infected  epithelial  cells  are  mostly  not  visibly  altered  ;  recently,  however, 
cases  have  become  known  in  which  they  have  become  hypertrophied  and  have  finally 
perished. — Laveran  and  Mesnil,  "  Sur  quelq.  particul.  de  I'evol.  d'une  greg."  (C.  R.  soc. 
biol.,  Paris,  1900,  lii.,  p.  554).  Siedlecki,  M.,  "  Sur  les  Yapp.  d.  greg.  avec  I'epith.  intest. 
(ibid.,  1901,  liii.,  p.  81).  Siedlecki,  M.,  "  Contrib.  a  I'etud.  d.  chang.  cellul.  prov.  p. 
1.  greg."  (Arch,  d'an.  micr.,  1901,  iv.,  p.  87).  Leger  et  Dubosq.,  "  Not.  sur  les  grillons. 
III.  Gregarina  Davini  "  (Arch.  Zool.  exp.,  1899,  ni-»  ser-  7  /  not-  et  revue,  p.  38). 


68  THE    ANIMAL    PARASITES    OF    MAN 

usual  condition,  in  so  far  as  the  sporozoites  likewise  do  not  penetrate  into 
the  epithelial  cells,  but  only  fasten  themselves  on  the  latter  by  one  pole,  which 
ultimately  becomes  the  epimerite.  Finally,  the  intra-cellular  phase  may  be 
of  short  duration,  and  multiplication  by  schizogony  may  take  place  during 
the  same.1 

For  the  classification  of  the  gregarinidia  refer  to  the  literature  as  follows  :  — 
/ 

LITERATURE. 

DUFOUR,  L.     Note  sur  la  greg.  (Ann.  sc.  nat.,  1828,  i,  xiii.,  p.  366). 

KOELLIKER,  A.   Beitr.  z.  Kenntn.    nied.    Th.  I.  Ueb.  d.  Gttg.  Gregarina  (Z.  f.  w.  Z., 

1848,  i.,  p.  i). 

STEIN,  F.  v.  Ueb.  d.  Nat.  d.  Greg.  (Arch.  f.  An.  u.  Phys.,  1848,  p.  182). 
LIEBERKUHN,  N.      Evol.   d.   Greg.  (Mem.   cour.   et  mem.   d.   sav.   etrang.   Acad.   belg., 

1855,  xxvi). 
SCHMIDT,  A.      Beitrag  zur  Kenntniss  der  Gregarinen  und  ihrer  Entwickelung  (Abhdl. 

d.  Senckenb.  naturf.  Ges.  in  Frankf.  a.  M.,  1854,  i.,  p.  161). 
BENEDEN,  E.  v.  Rech.  sur   1'evolution  des  Gregarines    (Bull.  Acad.  roy.  belg.,   1871, 

2,  xxxi.,  p.  325). 
GIARD,   A.     Contribution  a  1'hist.  nat.   des  Synascidies  (Arch.   d.   Zool.   exp.   et  gen., 

1872,  ii.,  p.  841). 
SCHNEIDER,  A.,  in  Arch,  de  Zool.  exp.  et  gen.,  1873,  ii.,  p.  515  ;  1875,  iv.,  p.  493  ;    1882, 

x.,  p.  423  ;  1884,  2,  ii..  p.i;  and  the  zoological  tables  issued  by  the  same  author). 
BUTSCHLI,  O.     Kleine  Beitr.  z.  Kenntniss  d.  Gregarinen  (Z.  f.  w.  Z.,  1881,  xxxv.,  p.  384). 
LEGER,  L.     Rech.  sur  les  gregarines  (Tabl.  zool.,  1892,  iii.,  p.  i). 
F'RENZEL,    J.     Ueber   einige   in   Seethieren   lebende   Gregarinen   (Arch.    f.    mikr.,    An. 

1885,  xxiv.,  p.   545).      Argentin.  Gregarinen  (Jen.  Zeitsch.  f.  Naturwiss,   1892, 

xxvii.,  p.  233). 
LEGER,  L.     Nouv.  rech.  sur  les  cyst  Polyparas.  d.    Arthrop.   terr.  (Ann.  de  la  Fac. 

d.  sc.  de  Marseille,    1899,  vi.,  No.  3.     Sur  un  nouv.   sporozoaire  des  larves  de 

clipter  (C.  R.  Ac.  sc.,  Paris,"  T.,  1900,  cxxxi.,  p.  722). 


Order  2.     Coccidiida. 

Hake(i)  first  saw  the  formations  we  now  term  Coccidia  during  his  investi- 
gations on  the  so-called  coccidial  nodules  of  rabbits.  The  opinions  as  to  the 
nature  of  these  peculiar  formations  were  very  diverse  ;  the  discoverer  con- 
sidered them  to  be  a  sort  of  pus  corpuscle  ;  Nasse  (2)  took  them  for  epithelial 
cells  of  the  biliary  passages,  others  for  helminthes,  especially  the  ova  of 
trematodes  (Dujardin,  Kuchenmeister,  Gubler,  &c.)-  Remak(3)  was  the  first, 
to  draw  attention  to  their  relation  to  the  Psorospermia  (Myxosporidia),  and 
this  investigator  found  them  also  in  the  small  intestinal  appendix  of 
rabbits.  Lieberkiihn  (4),  who  not  only  examined  the  coccidia  of  rabbits,  but 
found  similar  forms  in  the  kidneys  of  frogs,  likewise  calls  them  outright 
psorospermia ;  and  to  differentiate  Miiller's  psorospermia,  which  are  found 
in  fishes, 'from  those  of  rabbits,  &c.,  the  latter  were  called  oval  or  globular 
(Eimer)  (5),  until  R.  Leuckart  (6)  named  them  "  Coccidia  "  and  placed  them  in  a 
group  of  the  sporozoa  analogous  to  that  of  the  Gregarinida,  Myxosporidia, 
&c.  Numerous  works  confirmed  the  occurrence  of  coccidia,  not  only  in  all 
classes  of  vertebrate  animals,  but  also  in  invertebrates  (mollusca,  myria- 
poda,  annelida,  &c.),  and  numerous  genera  and  species  have  in  the  course 
of  time  been  described  which  inhabit  the  epithelium  of  the  intestine  and 

1  Compare  Caullery  and  Mesnil,  "  Le  paras.  intracelL  et  la  multi-pi,  asexue  d. 
(C.  R.  soc.  biol,  Paris,  1901,  liii.,  p.  84.) 


COCCIDIIDA 


69 


its  appendages  by  predilection,  but  are  also  found  in  other  organs  (kidneys, 
spleen,  ovaries,  vas  deferens,  testicles)  ;  some  also  live  in  the  connective 
tissue  of  various  organs,  more  particularly  of  the  intestine. 

The  knowledge  of  the  development  of  the  coccidia  was  of  particular  impor- 
tance in  determining  their  classification.  By  means  of  encysted  coccidia 
from  the  liver  of  rabbits,  Kauffmann  (7)  first  confirmed  the  fact  that  the  cystic 
membrane,  which  was  filled,  or  partly  filled,  with  granular  contents,  divided 
into  three  or  four  pale  bodies  after  a  long  sojourn  in  v/ater  ;  Lieberkiihn,  how- 
ever, observed  the  same  process  in  the  host  in  the  case  of  coccidia  of 
the  kidney  of  the  frog.  Stieda  (8)  studied  more  minutely  the  alterations  that 
take  place  within  the  encysted  coccidia  of  the  liver  of  rabbits  after  the 
death  of  the  host  ;  he  discovered  that  what  we  at  the  present  day  call 
"  spores  "  were  oval  formations  pointed  at  the  one  pole,  and  surrounded 
by  a  delicate  membrane,  which  exhibited  a  certain  thickness  at  the  pointed 
extremity  and  enclosed  a  -slightly  bent  rodlet,  expanding  at  either  end  into 
a  strongly  light-refracting  globule  ;  a  finely  granulated  globule  also  lay  in  the 
concavity  of  the  bent  .rodlet.  Waldenburg  (9)  saw  the  appearance  of  the  same 
phenomenon  in  coccidia  from  the  epithelium  of  the  villi  and  Lieberkuhn's 
glands  from  the  intestine  of  the  rabbit  ;  but  the  process  in  this  case  took 
place  in  a  much  shorter  time. 


j$8f 

FIG.  27. — Coccidium  cumculi  (Riv.),  from  the  f^V.'r-^ 
liver  of  the  rabbit,  in  various  stages  of  develop-  |''J':S&' 
ment. 


According  to  the  discovery  of  Kloss(io),  the  spores  of  the  coccidia  of  the 
urinary  organ  of  the  garden  snail  are  formed  in  far  greater  numbers  ;  the  round 
spores  also  harbour  several  (five  to  six)  rodlets,  which  after  the  bursting  of 
the  spore-envelope  become  free.  Eimer's  researches  have  made  us  acquainted 
with  a  coccidium  from  the  intestine  of  the  mouse,  which  was  transformed 
in  toto  into  a  "  spore,"  with  sickle-shaped  little  bodies  ;  the  fact  was, 
moreover,  established  that  the  little  bodies  left  the  delicate  envelope  already 
in  the  intestine,  made  crossbow  movements,  and  were  finally  transformed  into 
amoeboid  beings,  which  apparently  penetrated  the  epithelial  cells  ;  at  all 
events,  similar  bodies  of  various  sizes  were  seen  in  these  cells.  Taking  the 
immense  number  of  these  parasites  into  account  and  the  lack  of  any  other 
cause,  Eimer  attributed  the  sudden  death  of  his  mice  to  the  Gregarina  falci- 
formis,  as  the  parasite  was  then  called,  just  in  the  same  way  as  a  few 
years  previously  Reincke  (n)  ascribed  the  acute  intestinal  catarrh  of  rabbits 
leading  to  their  death  to  the  invasion  of  intestinal  coccidia. 

All  that  had  become  known  about  coccidia  up  to  1879  was  then  com- 
piled by  Leuckart,  and  completed  by  his  own  observations  on  the  liver  coccidia 
of  the  rabbit.  Experimental  infections  had  already  been  conducted  by  Walden- 
burg with  intestinal  coccidia  of  rabbits,  and  by  Rivolta  (12)  with  the  coccidia 
of  the  fowls,  which  experiments  confirmed  the  importance  of  the  spores,  or 


70  THE    ANIMAL    PARASITES    OF    MAN 

bodies,  enclosed  in  them  in  the  transmission  of  the  parasites  to  other  animals. 
Accordingly,  it  may  be  assumed  that  after  the  importation  of  the  spores  into 
the  intestine  the  sporozoites  are  set  free,  actively  penetrate  into  the  intes- 
tinal cells,  where  they  grow  into  coccidia,  and  finally  become  encysted. 
The  further  development,  i.e.,  the  formation  of  spores,  takes  place  outside 
in  these  cases  ;  in  other  cases  (Kloss,  Eimer)  it  takes  place  within  the 
host.  Although  much  regarding  the  cycle  of  development  was  still 
hypothetical,  the  theories  coincided  with  the  observations,  and  were  there- 
fore universally  regarded  as  confirmed.  Further  research  confirmed  this  view 
in  numerous  new  forms. 


FIG.  28. — Spores  of  the  Coccidium  cuniculi, 
(Riv.),  with  two  sporozoits  and  residual  bodies ; 
to  the  right  a  free  sporozoit.  (After  Balbiani.) 


L.  Pfeiffer's  statements  (13)  on  the  part  that  certain  coccidia  or  their 
sporozoites  played,  or  seemed  to  play,  as  causes  of  disease  furnished 
renewed  impetus  for  the  investigation  of  the  coccidia.  The  ingestion  of 
even  very  numerous  spores  did  not  appear  to  account  for  the  mass  infection 
so  frequently  observed,  even  after  Balbiani  (15)  had  confirmed  the  fact  that 
there  were  two,  not  one,  sporozoites  confined  in  every  spore  of  the  coccidia  of 
rabbits  (fig.  28).  The  hypothesis  was  therefore  advanced  that  the  sporozoites 
or  young  coccidia  were  able  to  divide  themselves  once  more  before  again 
sporulating.  The  question  was  finally  solved  quite  differently.  R.  Pfeiffer  (14) 
first  confirmed  the  fact  that  in  addition  to  the  well-known  method  of 


FIG.  29. — So-called  swarm  cysts  of 
the  Coccidium  of  the  rabbit.  (After  R. 
Pfeiffer.) 


sporulation  in  the  coccidia  of  the  rabbit  that  causes  the  infection  of  fresh 
hosts  (<f  exogenous  sporulation  "),  an  enormous  increase  may  follow  in  the 
already  infected  host  in  a  manner  that  Eimer  first  observed  in  the  coccidia 
of  the  intestine  of  the  mouse  ("  endogenous  sporulation ").  Whereas  it 
had  hitherto  been  believed  that  some  of  the  species  of  coccidia  increased 
like  Coccidium  oviforme  and  others,  like  Eimeria  falciformis,  and  this  difference 
had  been  made  the  foundation  of  the  classification.  R.  Pfeiffer  was  successful 
in  observing  the  occurrence  of  both  kinds  of  development  in  the  same 
species,  and  expressed  the  opinion  that  endogenous  sporulation,  which 
takes  place  within  the  host,  was  the  cause  of  the  mass-infection  that  is 
mostly  accompanied  by  serious  consequences  (fig.  29).  L.  Pfeiffer  sought, 


COCCIDIIDA  71 

above  all,  to  demonstrate  the  correctness  of  this  view  as  regards  other 
species  of  coccidia  also,  and  for  this  purpose  he  utilised  the  experiences 
already  published.  Coccidia  were  known  to  exist  in  a  number  of  different 
hosts,  and  to  propagate  in  some  according  to  the  Coccidium  type,  in  others 
according  to  the  Eimeria  type  ;  it  therefore  stands  to  reason  that  in  this 
case  it  was  not  the  question  of  two  species  belonging  to  different  genera 
living  side  by  side,  with  a  different  manner  of  development,  but  of  one 
species,  in  the  life  of  which  both  manners  of  development  occur  alternately, 

This  interpretation  of  facts  was  combated  especially  by  A.  Schneider  (16) 
and  by  Labbe  (17),  but  has,  nevertheless,  proved  true,  apart  from  the 
circumstance  that  Schuberg(iS)  succeeded  in  discovering  the  hitherto  unknown 
Coccidium  form  in  the  intestine  of  the  mouse  ;  and  that,  moreover,  Leger  con- 
firmed the  fact  that  there  are  no  arthropoda  in  which  Eimeria  are  not  found 
together  with  coccidia.  The  question  was  finally  settled  by  experiments  made 
by  Leger  (19)  with  the  coccidia  of  Scolopendra  cingulata,  by  Schaudinn  and  Sied- 
lecki  (20)  with  those  of  Lithobius  forcipatus,  and  by  Simond  (21)  with  the  coccidia 
of  the  rabbit.  On  Simond's  suggestion  the  sickle-shaped  germs  correspond- 
ing to  the  sporozoites,  which  are  formed  by  endogenous  sporulation,  are 
universally  termed  MEROZOITS  ;  and  in  accordance  with  Schaudinn's  suggestion, 
those  individuals  which  form  merozoites  are  termed  SCHIZONTS,  and  those 
which  produce  shelled  spores  are  called  SPORONTS.  In  contradistinction  to 
sporogony  (exogenous  sporulation),  one  therefore  speaks  of  schizogony 
(endogenous  sporulation). 

The  more  minute  examination  of  these  processes  at  last  led  to  the 
discovery  of  SEXUAL  DIMORPHISM,  of  copulation  and  alternation  of  genera- 
tion in  the  coccidia.  Schuberg  was  the  first  to  consider  the  possibility  of 
copulation  in  coccidia ;  in  addition  to  the  formations  which  now  are 
termed  merozoites,  he  observed  very  diminutive  bodies  ("  microsporozoites  ") 
in  the  coccidia  of  the  intestine  of  the  mouse,  which  were  able  eventually 
to  perform  copulation.  Labbe  confirmed  this  observation  in  some  of  the 
species,  and  Simond  (21)  expressed  the  opinion  that  "chromatozoites" 
occurred  in  all  coccidia.  Copulation  itself  was  then  observed  by  Schaudinn 
and  Siedlecki.  The  copulating  bodies  are  termed  gametes  :  as,  however, 
they  differ  considerably  one  from  the  other,  the  males  are  called  micro- 
gametes  (i.e.,  the  microsporozoites  of  Labbe  and  the  chromatozoites  of 
Simond)  and  the  females  macrogametes.  After  copulation  is  completed 
sporogony  takes  place,  and  in  the  cycle  of  development  of  one  species  this 
regularly  alternates  with  schizogony  (asexual  propagation). 

The  recognition  of  this  unsuspected  complicated  process  was  bound  to 
effect  reforms  in  the  classification  of  the  coccidia  ;  and  all  the  forms  that 
had  been  regarded  as  developmental  stages  (Eimeria,  &c.)  had  to  be 
eliminated  from  the  system. 

LITERATURE. 

(1)  HAKE.    A  Treat,  on  Varic.  Capill.  as  constit.  the  Structure  of  Carcinom.  of  the  Hep. 

Ducts,  with  an  Account  of  a  New  Form  of  the  Pus  Globule.     London,  1839. 

(2)  NASSE,  H.    Ueb.  d.  eiforrn.  Zellen  d.  tuberkelahnlichen  Ablagerungen  in  d.  Galleng. 

d.  Kaninchen  (Arch.  f.  An.  u.  Phys.,  1843,  P-  209)' 

(3)  REMAK,  H.     Diagn.  u.  pathogen.  Unters.     Berlin,  1845. 

(4)  LIEBERKUHN,  N.     Ueb.  d.  Psorospermien  (Arch.  f.  An.  u.  Phys.,   1854,  p.  i). 

Evol.  des  Greg.  (Mem.  cour  et  Mem:  d  sav.  etrang.  Ac.  d.  Belg.,  1855,  xxvi. 


72  THE   ANIMAL    PARASITES   OF    MAN 

(5)  EIMER,  TH.     Ueb.  d.  ei-  u.  kugelform.  Psorsp.  d.  Wirbelth.     Wiirzb.,  1870. 

(6)  LEUCKART,  R.     Die  Paras,  d.  Menschen,  &c.,  1879,  ii.,  2nd  edition,  p.  248. 

(7)  KAUFFMANN,  W.     Anal,  ad  tubercul.  et  entoz.  cognitionem.     Diss.  in  Berol.,  1847. 

(8)  STIEDA,  S.     Ueber  d.  Psorosp.  d.  Kaninchenleber  (Virchow's  Arch.  f.  path.  An., 

1865,  xxxii.,  p.  132). 

(9)  WALDENBURG,  L.     De  struc.  et  origirie  cystidum  verminos.     Diss  in  Berol,  1660. 

(Virchow's  Arch.  f.  path.  An.,    1862,  xxiv.,  p.    149). 
Zur  Entw.  d.  Psorosp.  (ibid.,  1867,  xl.,  p.  435). 
(10)   KLOSS,  H.     Ueb.  d.  Paras,  d.  Niere  von  Helix  (Abhandl.  d.  Senckenb.  natnrf.  Ges. 

Frankf.  a.  M.,  1855,  i.,  p.  189). 
(n)  REINCKE.     Nonnulla  quaed.  de  psorosp.  cuniculi.     Diss.  in  Kiliae,  1866. 

(12)  RIVOLTA,  G.     Psorospermi  i  psorospermosi  negli  anim.  dom.  (Med.  veter.,  1869,  3, 

.      iv.). 

(13)  PFEIFFER,   L.     Beitr.    z.    Kenntn.    d.    pathol.    Greg.  ;     II.     Ueber     Gregarinose, 

ansteckendes  Epitheliom  u.  Flag.-Diphth.  d.  Vogel  (Zeitschr.  f.  Hyg.  u.  Inf., 
1889,  v.,  p.  363). 
Die  Protozoen  als  Krankheitserr.      ist  edition,  Jena,  1890  ;     2nd  edition,  1892. 

(14)  PFEIFFER,  R.     Beitr.  z.  Protozoenforsch.   I.  Die  Coccidienkrankh.  d.  Kaninchen 

Berlin,   1892. 

(15)  BALBIANI,  G.     Le^.  sur  les  Sporoz.     Paris,  1884,  p.  104. 

(16)  SCHNEIDER,  A.     Le  cycle    evolut.  d.  Cocc.  et  M.  L.  Pfeiffer  (Tabl.  zool.  ii.,   p. 

105). 

(17)  LABBE,  A.     Rech.  zool.,  cytol.  et  biol.  sur  les  Cocc.  (Arch.  Zool.  exp.,  1896,  3,  iv.,  p. 


(18)  SCHUBERG,  A.    Die  Coccid.  aus  Darm  der  Maus  (Verh.  nat.-med.  Ver.  Heidelberg. 

N.  F.,  1895,  v.,  p.  369). 

(19)  LKGER,  L.     Le  cycl.  evol.  d.  Cocc.  chez.  les  arthrop  (C.  R.  soc.  biol.,  Paris,  1897, 

10,  iv.,  p.  382). 
Cocc.  nouv.  du  tub.  dig.  d.  Myriap.  (C.  R.  Ac.  sc.,  Paris,  1897,  cxxiv.,  p.  901). 

(20)  SCHAUDINN,   F.,   and    M.   SIEDLECKI.      Beitr.   z.   Kenntn.   d.  Cocc.    (Verh.  d.   D. 

zool.  Ges.,  1897,  vn-'  P-  J92)- 

SCHAUDINN,  F.     Unters.  lib.    d.  Generationswechsel  bei  Cocc.  (Zool.   Jahrb.  An., 
1900,  part  13,  p.  197). 

(21)  SIMOND,  P.  L.     L'evol.  d.  sporoz.  du  genre  Coccidium  (Ann.  Inst.  Pasteur,  1897, 

xi.,  p.  545). 

Occurrence  of  the  Coccidiida.  --  The  Coccidiida  in  their  mature 
condition  usually  live  within  the  epithelial  cells  of  various  organs,  and 
by  predilection  inhabit  those  of  the  intestine  and  of  its  dependent 
organs  ;  they  also  occur  frequently  in  the  excretory  organs  of 
the  mammalia,  birds,  amphibia,  molluscs,  arthropoda,  and  may 
also  be  found  in  the  scrotum  and  vas  deferens,  but  the  state- 
ment that  they  live  in  hen's  eggs,  as  well  as  in  the  oviducts  of 
fowls,  has  not  been  confirmed.1  Some  species  inhabit  the  nucleus, 
others  live  in  the  connective  tissue,  but  their  presence  in  the  latter 
situation  is  probably  only  secondary,  that  is,  they  have  only 
reached  it  from  the  epithelium  of  the  affected  organs. 

1  Notwithstanding  the  progress  made  during  the  last  decades,  the  ova  of  helmirithes 
and  more  particularly  of  trematodes,  have  been  mistaken  for  coccidia.  Thus  Posch- 
inger  (Zool.  Am.,  1886,  ix.,  p.  471)  and  Gebhard  (Virchow's  Arch.,  1897,  No.  147, 
p.  536)  mistook  the  ova  of  Distomum  turgidum,  Brds.,  for  coccidia.  Podwyssotzki 
(Centralbl.  /.  allg.  Path.,  1890,  i.,  p.  135)  made  a  similar  error  with  the  ova  (and  vitelline 
sacs)  of  a  species  of  Prosthogonimus  (Dist.  ovatum  of  the  authors);  von  Willach  (Arch. 
f.  wiss  u.  prakt.,  Thierheilk,  1892,  xviii.,  p.  242)  took  the  ova  of  a  nematode  for  coccidia. 
These  errors  are  merely  alluded  to  as  a  warning.  A  closer  examination  of  the  objects 
and  a  knowledge  of  such  mistakes  will  ensure  their  avoidance. 


COCCIDIIDA 


.»-,.-— , ...,•    .  **»• 


FIG.  30. — Scheme  of  the  development  of  Coccidium  schubergi,  Schaud.  (from  the 
intestine  of  Lithobius).  (After  Schaudinn.)  The  infection  is  caused  by  a  cyst  (xx.), 
containing  spores,  which  invades  the  intestine  of  a  Lithobius,  where  it  bursts  and  dis- 
charges the  sporozoites  (i.).  n.,  A  sporozoit  invading  an  intestinal  epithelial  cell; 
in.,  intestinal  epithelial  cells  with  young  coccidia  ;  iv.,  intestinal  epithelial  cells 
with  a  globular  schizont  ;  v.,  nuclear  segmentations  within  the  schizont  ;  vi.,  the 
daughter  nuclei  arranging  themselves  superficially  ;  vn.,  formation  of  the  mero- 
zoites  ;  vin.,  merozoites  that  have  become  free,  and  which,  penetrating  into  other 
epithelial  cells  of  the  same  intestine,  repeat  the  schizogony  (ii.-vm.)  ;  ix.  and  x., 
merozoites  which,  likewise  invading  the  epithelial  cells  of  the  same  intestine,  become 
individually  sexually  differentiated  ;  xia.,  adolescent  macrogamete  ;  xib.,  older 
macrogamete  ;  xic.,  mature  macrogamete  (discharging  particles  of  nucleus)  ;  xiia., 
young  microgametocyte  ;  xijb.,  older  microgametocyte  ;  xnc.,  increase  of  nuclei 
in  the  microgametocyte  ;  xnd.,  the  globular  residual  body  around  which  numerous 
microgametes  have  formed  ;  xiie.,  an  isolated  microgamete  ;  xin.,  the  mature 
macrogamete  surrounded  by  numerous  microgametes  and  forming  a  fecundating 
prominence  ;  xiv.,  the  nucleus  of  a  microgamete  that  has  penetrated  amalgamated 
with  the  nucleus  of  the  macrogamete  (fecundation) — the  latter  casts  off  a  membrane 
and  becomes  a  sporont  (oocyst)  ;  xv.,  xvi.,  xvn.,  nuclear  segmentation  in  the 
sporont  ;  xvin.,  sporont  with  four  sporoblasts ;  xix.,  the  sporoblasts  transformed 
into  spores  ;  xx.,  the  cysts  introduced  into  the  intestine  that  has  liberated  the  sporo- 
zoites by  bursting. 


74  THE   ANIMAL   PARASITES    OF   MAN 

The  SIZE  OF  THE  COCCIDIIDA,  corresponding  as  a  rule  to  the  habi- 
tat, is  usually  small,  but  there  are  species  that  attain  a  diameter  of 
i  mm.  Their  FORM  is  globular,  oval,  or  elliptical.  External  appen- 
dages are  lacking,  at  least  during  the  vegetative  period  of  their 
life,  which  is  spent  in  epithelial  cells,  within  which  they  increase 
in  size  ;  as  a  rule  only  one  is  present  in  each  cell,  rarely  more. 
The  BODY  SUBSTANCE  is  composed  of  a  more  or  less  finely  granu- 
lated or  distinctly  alveolar  protoplasm  which  exhibits  no  differen- 
tiation in  ecto-  and  endo-sarc.  All  species  possess  a  nucleus  that 
enlarges  with  their  growth  ;  sometimes  it  only  shows  through  the 
plasma  as  a  lighter  spot,  or  may  even  be  quite  concealed.  It  is 
vesicular  in  shape,  and  besides  containing  very  delicate  threads  of 
chromatin  in  the  light  coloured  nuclear  juice,  it  contains  generally 
only  one  large  nucleolus  (caryosoma). 

The  affected  epithelial  cells  degenerate  sooner  or  later  as  the 
parasite  feeds  on  them.  After  having  had  their  form  changed  by 
the  growing  parasite  they  finally  perish.  The  cellular  membrane 
then  alone  surrounds  the  coccidia,  which,  at  least  in  the  species 
sufficiently  known,  begin  to  propagate  by  an  asexual  process 
(SCHIZOGONY)  ;  hereby  the  parasites  themselves  become  schizonts, 
as  the  initial  stage  is  usually  called.  They  differ  from  later  stages 
(sporonts),  which  resemble  them  in  form,  by  the  absence  of  granu- 
lations in  the  plasma,  as  well  as  by  the  vesicular  nucleus.  The 
form  is  not  always  alike,  for  in  some  cases,  at  least,  many  schizonts 
assume  a  globular  form. 

SCHIZOGONY  (fig.  30)  commences  with  a  division  of  the  nucleus, 
which  nevertheless  takes  place  in  different  ways  in  the  different 
species,  and  finally  leads  to  the  formation  of  numerous  daughter 
nuclei  which  become  smaller  and  smaller,  and  which  collect  beneath 
the  surface  of  the  schizonts,  but  in  some  species  collect  only  at  one 
half.  A  part  of  the  protoplasm  of  the  periphery  now  divides  around 
each  daughter  nucleus,  the  remaining  part  (residual  body)  being 
left  in  the  centre  or  on  one  side.  The  segments  of  the  divided 
plasm,  each  containing  a  nucleus,  assume  a  fusiform  shape  and 
become  merozoits,  which  very  soon  gain  their  freedom  and  quit 
the  residual  body  (fig.  30,  vii.). 

The  merozoits  move  in  a  manner  similar  to  that  of  the 
sporozoites,  from  which  they  are,  however,  distinguished  by  a 
somewhat  different  shape  and  the  form  of  their  nucleus.  The 
movements  consist  either  of  slow  incurvations  with  subsequent 
straightenings,  or  annular  contractions  along  the  entire  extent  of 
the  body  ;  in  addition,  there  are  gliding  movements  similar  to 


COCCIDIIDA  75 

those  of  many  gregarines,  and  brought  about  in  a  like  manner 
by  the  secreting  at  the  posterior  extremity  of  a  gelatinous  fila- 
ment that  stiffens  rapidly.  The  merozoits  do  not  gain  the  open 
in  the  usual  way,  but  are  destined  to  still  further  infect  the 
same  host  by  actively  penetrating  into  other  epithelial  cells 
of  the  affected  organ  ;  here  they  continue  their  growth  and  may 
again  and  again  undergo  schizogony.  In  the  Infusoria  the 
repeated  segmentations  finally  cease  and  are  again  renewed  only 
after  a  conjugation  :  this  is  likewise  the  case  with  the  coccidia, 
with  the  difference  that  in  the  latter  the  two  uniting  individuals 
(gametes)  are  differently  constituted  one  from  the  other,  whereas 
in  the  infusoria  they  are  almost  always  similar. 

When  the  schizogony  ceases,  the  merozoits  that  had  penetrated 
the  epithelial  cells  and  there  grown  consist  of  two  kinds 
of  beings  differently  constituted  ;  one  kind  possessing  a  light 
plasm  (fig.  30,  xii.),  the  other  an  opaque  plasm  richly  granu- 
lated, while  both  possess  a  vesicular  nucleus  with  caryosoma 
(fig.  30,  XL).  In  order  to  continue  their  development  the  dark 
individuals  must  copulate,  and  are  therefore  termed  either  female 
gametes  or,  on  account  of  their  size,  macrogametes .  The  hyaline 
individuals,  the  male  individuals  (microgametes)  necessary  to  con- 
jugation, are  formed  in  greater  numbers.  They  are  slender  bodies 
consisting  chiefly  of  nuclear  substance,  which  in  most  species  bear 
two  flagella  of  unequal  length  directed  backwards,  and  the  place 
of  insertion  of  which  varies  according  to  the  species  (fig.  30,  xxe.). 

While  the  development  of  the  microgametes  is  rapicUy  advanc- 
ing a  change  of  the  nucleus  occurs  in  the  macrogametes,  parts 
of  the  caryosoma  (nucleolus)  are  extruded,  and  the  nucleus  loses 
at  the  same  time  its  vesicular  shape.  By  this  time  the  macro- 
gametes  are  capable  of  conjugation,  and  the  process  takes  place 
within,  the  host,  generally,  however,  outside  the  affected  and  degen- 
erated host  cells.  The  microgametes  that  have  now  become  free, 
leaving  a  very  large  residual  body,  crowd  around  the  mature 
macrogametes,  which  project  a  small  prominence  (fecundating 
protuberance)  for  their  reception  (fig.  30,  xm.).  As  soon  as  a  micro- 
gamete  comes  into  touch  with  this  and  penetrates  into  the  plasm  of 
the  macrogamete,  the  latter  surrounds  itself  with  a  membrane 
which  prevents  the  intrusion  of  other  microgametes.  The  nucleus 
of  the  microgamete  that  has  gained  entry  amalgamates  with  the 
nucleus  of  the  macrogamete,  which  is  then  capable  of  forming  the 
well-known  spores  with  shells  ;  it  is  therefore  called  sporont  (also 
oocyst  or  copula). 


76  THE    ANIMAL    PARASITES    OF    MAN 

The  reduced  nucleus  of  the  macrogamete  expands  itself  on 
the  entry  of  the  microgamete,  and  becomes  a  spindle  to  which 
the  nuclear  parts  of  the  microgamete  become  attached  (fig.  30, 
xiv.  and  xv.).  Thereupon  the  spindle  divides  into  two  daughter 
nuclei  which  assume  a  round  shape.  The  protoplasm  at  this  stage 
may  at  once  divide,  or  another  segmentation  of  the  daughter 
nuclei  may  previously  occur.  In  the  former  case  the  two  halves 
divide  again,  so  that  finally  four  nucleated  segments,  the  sporo- 
blasts,  are  formed,  whereas  in  the  other  case  the  four  sporoblasts 
appear  simultaneously.  In  both  cases  a  residual  body  of  varying 
size  is  separated  from  the  protoplasm  of  the  sporont.  As  a  rule, 
in  the  meantime,  the  encysted  sporonts  have  already  been  dis- 
charged outwardly,  and  there,  and  in  the  manner  described  above, 
form  the  sporoblasts  after  a  longer  or  shorter  period  of  incuba- 
tion. The  sporoblasts  are  originally  naked,  but  they  soon  secrete 
a  homogeneous  membrane  in  which  they  become  enveloped  (fig.  30, 
xviii.).  After  the  segmentation  of  the  nucleus  their  contents 
divides  into  two  sickle-shaped  sporozoits,  in  addition  to  which  there 
is  generally  also  a  residual  body  (fig.  30,  xix.). 

This  terminates  the  development  ;  the  spores  are  intended  for 
the  infection  of  other  hosts.  If  they  attain  the  intestine  of 
suitable  hosts,  free  or  enclosed  in  the  cystic  membrane  of  the 
sporont,  the  actions  of  the  intestinal  juices  cause  them  to  open 
and  permit  the  sporozoites  to  escape.  The  latter  move  exactly 
like  the  merozoites  and  soon  make  their  way  into  epithelial  cells, 
where  they  become  schizonts. 

Although  our  knowledge  of  the  development  of  the  coccidia 
is  but  of  recent  date,  yet  it  already  extends  to  a  large  number 
of  species,  which  exhibit  varying  deviations  from  the  cycle  of 
development  described  above.  The  most  important  deviation  is 
the  simplification  by  the  omission  of  .schizogony,  as  in  Legeria 
octopiana,  which  lives  in  the  submucosa  of  the  intestine  of  cuttle- 
fish. In  these  the  sporozoites  that  have  invaded  the  epithelial 
cells  are  transformed  direct  into  macrogametes  or  microgametocytes, 
which,  after  the  disintegration  of  the  cells  of  the  host,  reach 
the  submucosa,  where  they  continue  their  transformation,  copulate 
and  sporulate.  Yet  in  this  species  auto-infection  of  the  host  is 
not  lacking,  at  all  events  it  has  been  stated  that  if  the  oocyts 
furnished  with  numerous  spores  penetrate  from  the  submucosa  into 
the  intestinal  lumen,  they  find  themselves  in  the  same  condition 
as  if  they  had  been  introduced^  per  os,  that  is  to  say,  the  spores 
open  themselves  and  their  sporozoites  infect  other  cells. 


COCCIDIUM    CUNICULI 


77 


In  order  to  systematically  classify  the  coccidia  the  form  and 
number  of  the  spores  and  the  number  of  sporozoites  are  taken 
into  account.  Accordingly  the  following  are  differentiated  :— 

I. — Disporea,  forming  only  two  spores. 

(1)  Cyclospora,  Schndr.,  each  with  two  sporozoites. 

(2)  Isospora,  Schndr.,  each  with  four  sporozoites. 

II. — Tetrasporea,  forming  four  spores. 

(3)  Coccidium,   Lckt.,   each  with   two   sporozoites  ;     spores   globular   or 

oval. 

(4)  Crystallospora,   Labbe,    each   witti    two   sporozoites  ;     spores   in    the 

shape  of  a  double  pyramid. 

III. — Polysporea,  forming  more  than  four  spores. 
(a)  Oocysts,  with  sporoducts. 

(5)  Gymnospora,  Mon.  (probably  a  Gregarinida). 
(6)  Oocysts,  without  sporoducts. 

(6)  Barrouxia,  Schndr.,  spores  with  one  sporozoite. 

(7)  Adelea,  Schndr.,  spores  with  two  sporozoites. 

(8)  Legeria,  R.  Blanch.    (=  Benedenia,  Schndr.,  nee  Dies.),  spores  globular, 

with  three  sporozoites. 

(9)  Klossia,  Schndr.,  spores  round,  with  four  sporozoites. 

(10)  Hyaloklossia,  Labbe,  spores  oval,  with  two  or  four  sporozoites. 

IV. — Asporocystidea,  forming  numerous  naked  sporozoites. 

(n)  Legerella,M.esn. 

THE  COCCIDIA  OBSERVED  IN  MAN. 
Gen.  Coccidium  (R.  Lckt.   1879). 

Spores  of  a -fusiform,  oval,  or  globular  form,  in  each  of  which  there  are  two 
sporozoites,  in  addition  to  a  roundish  residual  body.  The  species  live  in  the 
intestine,  liver  and  kidney  of  vertebrate  and  invertebrate  animals  ;  a  few  give 
rise  to  epidemic  diseases,  more  particularly  in  domestic  animals. 

i.  Coccidium  cuniculi  (Rivolta,  1878). 

Syn.  Psorospermium  cuniculi,  Riv.,  1878  ;  Coccidium  oviforme,  R.  Lckt., 
1879- 

In  this  species  the  fertilised  sporont  stage  (oocyst)  has  been 
known  the  longest  and  is  found  in  .the  coccidium  nodules  so 
common  in  the  liver  of  rabbits.  It  is  oval,  0-033 — 0-049  mm. 
in  length,  0-015 — 0-028  mm.  in  breadth,  and  surrounded  by  an 
integument  with  a  double  outline  which,  according  to  some  state- 
ments, has  an  opening  at  the  pointed  pole  (fig.  31,  a,  b).  The 
plasm,  which  is  somewhat  coarsely  granular,  entirely  fills  the 
integument  or  is  gathered  together  into  a  round  central  mass. 
At  this  stage  the  parasites  are  evacuated  in  the  natural  way 


THE    ANIMAL    PARASITES    OF    MAN 


and  sporulate  in  the  open  within  a  fortnight  or  three  weeks. 
The  fully-developed  spores  are  of  a  broad  fusiform  shape  and 
measure  0-012 — 0-015  m*n.  in  length,  with  a  breadth  of  0-007 
mm.  They  contain  two  sporozoites,  broad  at  one  end,  pointed 
at  the  other,  which  lie  in  such  a  position  that  they  form  a  bent 
dumb-bell-shaped  body  (fig.  32).  A  granulated  residual  body  lies 
in  the  concavity.  In  sporulation  the  whole  of  the  plasm  of  the 
sporont  is  taken  up,  and  therefore  in  the  oocyst  there  is  no 
residual  bodv. 


FIG.  3!. — Coccidium  cuniculi  (Riv.),  from  the  liver  of  the  rabbit,  sporulating 
(a)  Entirely  occupying  the  integument  (oocyst)  ;  (&)  gathered  together  in  a  nucleated 
ball  ;  (c)  divided  into  four  spores. 

>?-   FIG.   32. — -Spores  of  the  Coccidium  cuniculi  (Riv.),  with  two  sporozoites  and  resi- 
dual bodv  •    a  free  sporozoite  to^the  right  (after  Balbiani). 

The  development  of  this  species  does  not  deviate  from  the 
course  sketched  above.  Infection  occurs  through  swallowing  spores 
or  oocysts  containing  spores.1  The  gastric  juice,  as  already  stated 
by  Rieck,  causes  the  spores  to  open  and  the  sporozoites  to  become 
free  ;  the  latter  then  utilise  the  ductus  choledochus  to  reach  the 
biliary  ducts,  where  they  penetrate  the  epithelial  cells  and  propagate 
by  means  of  schizogony.2 

According  to  the  number  of  spores  taken  up  there  ensues, 
sooner  or  later,  at  those  parts  of  the  biliary  ducts  that  are 
attached,  inflammation  with  proliferation  of  the  epithelium  and  con- 
nective tissue  of  the  passages,  which  become  greatly  thickened  at 
the  expense  of  the  substance  of  the  liver.3  Finally,  irregular 

1  Pianese's  statement  (Arch.  d.  parasit.,  1899,  u->  P-  397)  that  the  ingestion  of  oocysts 
before   they   have   sporulated   causes   infection    still   lacks   confirmation.     It   cannot, 
indeed,  be  denied  that  the  animals  experimented  on  finally  became  infected,  but  the 
necessary  assumption  that  the  oocysts  developed  further  in  the  intestine  is  highly 
improbable.     I  consider  it  much  more  probable  that  the  oocysts  ingested  were  passed 
through    the   intestine,  sporulated   outside,  and    were   then    again  .taken   up  by  the 
animals  experimented  on. 

2  Podwyssotzki,  W.,  "  Z.  Entw.  d.  Cocc.  ovif.  ah  Zellschmar otter  "  (Bibl.  med.  Cassel, 
1895,  part  D.,  ii.,  No.  4) ;  Pianese,  G.,  "  Le  fasi  di  svil.  del  Cocc.  ovif."  (Arch,  de  paras., 
1899,  ii.,  p.  397). 

3  Felsenthal   and   Stamm,    "  Verdnd.   in  Leber  u  Darm.   b.  d.    Coccidienkrankh.  d, 
Kaninch."  (Vtrchow's  Arch.  f.  path.  Anat.,  1893,  cxxxii.,  p.  36). 


COCCIDIUM     CUNICULI  79 

or  roundish  thick-walled  nodules,  more  or  less  isolated,  and  con7 
taining  a  caseous  material,  are  formed  ;  this  material  consists  of 
detritus,  pus  cells,  epithelial  cells  and  coccidia  in  various  stages 
of  development,  according  to  the  time  that  has  elapsed  from  the 
moment  of  infection.  In  originally  severe  infection  which  increases 
rapidly  in  consequence  of  schizogony,  the  inflammation  of  the 
liver  is  great  and  leads  to  serious  illnesses  and  frequently  to 
death  ;  in  other  cases  auto-division  finally  sets  in,  as  schizogony 
cannot  continue  indefinitely,  though  the  coccidia  nodules  persist. 

The  transmission  of  Coccidium  cuniculi  to  man  occurs  very 
rarely,  at  all  events  the  number  of  cases  known  are  few.  The 
following  cases  are  probably  correct  :— 

(1)  Gubler's    Case.      A  stone-breaker,    aged  45,  was  admitted   to  a  Paris 
hospital  suffering  from  digestive  disturbances  and  severe  anaemia.    On  examin- 
ation   the  'liver    was     found    to    be    enlarged     and     presented    a    prominent 
swelling,    which    was    regarded    as    echinococcus.      At    the    autopsy    of    the 
man,    who   succumbed    to   intercurrent   peritonitis,    twenty   cysts   were    founq1 
averaging    2  —  3    cm.    in    diameter,    and   one    measuring    12 — 15    cm.     The 
caseous    contents     consisted    of    detritus,    pus    corpuscles,    and    oval-shelled 
formations,    which    were    considered    to    be    distomum    eggs,    but    which,    in 
accordance   with   Leuckart's    conjecture,   proved    to   be  .coccidia   (Gubler,  A., 
"  Tumeurs   du   foie   determ   par   des   ceufs   d'helm  ."    [Mem.  soc.  biol., 
Paris,    1858,    v.,    2;    and    Gaz.med.de   Paris,    1858,    p.    657);    Leuckart,  R., 
Die   menschl.  Paras.,  1863,    ist   edition,   i.,   p.-  49,   Anm.J. 

(2)  Dressler's   Case   (Prague).       Relates   to   three  cysts,   varying    from   the 
size  of    a  hemp-seed   to   that  of    a  pea,    and   containing  coccidia,   found    in 
a    man's    liver    (Leuckart,    R.,    Die    menschl.    Paras.,    1863,    ist    edition,   i., 
p.  740). 

(3)  Sattler's    Case    (Vienna).     Coccidia  were  in   this    case  observed  in    the 
dilated    biliary   duct    of    a    human    liver   (Leuckart,    R.,   Die   thier.   paras,    d. 
Mensch.,  1879,  ist    edition,   ii.,    p.    281). 

(4)  Perls'  Case  (Giessen).     Perls  discovered  coccidia  in  an  old  preparation 
of   Sommering's   agglomerations   (Leuckart,   R.,   ibid.,   p.    282). 

(5)  Silcock's   Case   (London).      The   patient,   aged    50,    who    had   fallen  ill 
with  serious  symptoms,  exhibited  fever,  enlarged  liver  and  spleen,   and  had 
a    dry,    coated    tongue.     At    the    autopsy    numerous    caseous   centres,   mostly 
immediately  beneath   the  surface,  were  found,  while   the  contiguous  parts  of 
the    liver    were    inflamed.      The     microscopical     examination     demonstrated 
numerous  coccidia  in   the  hepatic  cells  as  well   as  in   the  epithelium  of  the 
biliary  ducts.     A  deposit  of  coccidia  was  likewise  found  in  the  spleen,  which 
the    parasites    had    probably    reached    by  means  of    the    circulation    of    the 
blood  '   (Silcock,   "  A  Case  of  Parasit.  by  t'sorospermia  "  (Trans.  Path.  Soc., 
London,    1890,   xxi.,   p.    320). 

Other    cases    are    more    or    less    dou    :.    I,    such    as    Virchow's    (Arch.    f. 

1  Pianese  has  confirmed  the  fact  that  coccidia  actually  occur  in  the  blood  of  the 
hepatic  veins  of  infected  rabbits. 


80  THE   ANIMAL    PARASITES    OF    MAN 

path.  An  ,  1860,  xviii.,  p.  523),  in  which  a  thick-walled  tumour,  measuring 
9 — ii  mm.,  was  found  in  the  liver  of  an  elderly  woman.  Long  oval  forma- 
tions surrounded  by  two  membranes,  measuring  0-056  mm.  in  diameter, 
and  containing  a  number  of  small  roundish  bodies  were  found  in  the 
tumour.  Virchow  is  of  opinion  that  these  foreign  bodies  were  develop- 
mental forms  of  the  ova  of  pentastomes l  rather  than  coccidia. 

The  coccidia  which  Podwyssotzki  states  that  he  found  in  the  hepratic 
cells  and  in  their  nuclei  are  also  problematical  (Podwyssotzki.,  "  Ueb.  d. 
Bedeut.  d.  Coccid."  in  d.  Path.  d.  Leber  d.  Mcnschen,  C.  f.  B.  u  P., 
1889,  vi.,  p.  41).  The  parasite  is  termed  Caryophagus  hominis. 

An  observation  by  Thomas,  of  the  presence  of  "  Coccidium  ovi forme  "  in 
a  cerebral  tumour  the  size  of  a  pea,  and  surrounded  by'  a  bony  substance, 
occurring  in  a  woman,  aged  40,  must  admit  of  another  explanation. 
(Thomas,  J.,  "Case  of  Bone  Formation  in  the  Human  Brain  due  to  the 
Presence  of  Cocc.  ovif."  Journ.  Boston  Soc.  Med.  Sc.,  1899,  in.,  p.  167  ; 
C.  /.  B.,  P.  u.  J.,  1900,  p.  xxviii.,  1882). 


2.  Coccidium  hominis  (Rivolta,  1878). 
Syn.  :  Cystospermium  hominis,  Riv.,  1878  ;  Coccidium  perforans,  R.  Lckt.,  ]  879. 

Remak  was  the  first  observer  to  confirm  the  fact  that  this 
species  inhabits  the  intestinal  epithelial  cells  of  rabbits,  giving 
rise  to  severe  diarrhoea,  which  usually  causes  death.  A  few  later 
authors  consider  that  the  parasite  is  identical  with  Coccidium 
cuniculi,  but  there  are  differences  between  the  two  forms  which 
justify  the  formation  of  a  separate  species. 

Apart  from  its  habitat,  the  difference  consists  in  the  smaller 
size  of  the  oocysts  (0-024 — 0-026 — 0-035  mm-  m  length,  and 
0-0128  —  0-014  —  0-002  mm.  in  breadth),  in  its  more  rounded 
form,  and  in  the  residual  body  that  is  always  present  after  sporu- 
lation  and  absent  in  Coccidium  cuniculi.  Moreover,  the  time 
employed  for  the  segmentation  of  the  globular  cystic  contents 
into  sporoblasts  differs  in  the  two  species  ;  in  Coccidium  hominis 
the  time  taken  is  three  or  four  days,  in  Coccidium  cuniculi  three 
or  four  weeks.  In  other  particulars  the  two  species  agree. 

As  Railliet  and  Lucet  have  demonstrated,  infection  is  brought 
about  by  the  ingestion  of  mature  spores.  In  consequence  of  the 
schizogony  such  a  severe  auto-infection  follows  within  a  few  days 
that  the  entire  small  intestine  is  affected.  Even  with  the  naked 
eye  whitish  spots  may  be  observed  in  the  mucous  membrane 
caused  by  the  wholesale  colonisation  of  schizonts  and  sporonts  in 
the  cellular  epithelium  as  well  as  in  Lieberkuhn's  glands.  The 

1  Compare  trematodes  of  man. 


COCCIDIUM    BIGEMINUM  8l 

intestinal  lumen  is  sometimes  entirely  filled  with  free  parasites,  and 
frequently  more  than  one  schizont  is  met  with  in  each  epithelial 
cell.  In  such  severe  cases  death  occurs  after  a  few  days,  in 
milder  cases  the  diseased  animals  sink  gradually,  or  may  spon- 
taneously recover. 


FIG.  33. — Coccidium  hominis  (Riv.)  in  sporulation.     (After  Riek.) 

The  coccidia  observed  in  the  intestine  of  the  horse,  goat,  ox, 
sheep,  pig,  mole,  marmot,  guinea-pig  and  weasel  are  generally 
regarded  as  varieties  of  Coccidium  hominis,  i.e.,  C.  perforans. 

Eimer  found  the  intestinal  epithelium  of  two  cadavers  of  human  beings  of  the 
Pathological  Institute  in  Berlin  permeated  with  coccidia  (Die  ei.  u.  kugelf.  Psorosp. 
1.  Wirbelth.,  1870,  p.  16).  Railliet  and  Lucet's  case  was  undoubtedly  attribut- 
able to  intestinal  coccidia.  In  this  case  a  woman  and  her  child  had  both 
been  suffering  from  chronic  diarrhoea  for  a  long  time,  and  coccidia  were 
found  in  the  faeces  of  both  (Railliet,  Trait  Zool.  med.  et  agric.,  1893,  2nd 
edition,  p.  140).  In  other  cases  (Grassi,  Rivolta)  in  which  only  the  occur- 
rence of  coccidia  in  the  faeces  is  reported,  the  origin  of  the  parasites — 
whether  from  the  intestine  or  liver — remains  doubtful,  and  likewise  also- 
the  species  to  which  they  belong. 

3.   Coccidium  bigeminum,  Stiles,  1891. 
Syn :   Cystospermium   villorum   intestinalium   canis   et  felis,   Rivolta,   1874. 

This  species  has  been  known  since  1854  (Finck,  Sur  la  phys, 
de  Vcpith.  intest.,  These,  Strasburg,  p.  17)  ;  it  lives  in  the  intes- 
tinal villi  of  dogs,  cats  and  the  pole-cat  (Mustela  putorius,  L.), 
and  is  distinguished  by  its  small  size  and  its  constant  appearance 
in  pairs.  According  to  Stiles,1  the  oocyst  divides  into  two  equal 
portions  which  become  encysted  and  then  form  four  spores.  The 
oocysts  of  this  species  attain  a  length  of  0*012 — 0-015  mm.  and 
a  breadth  of  0-007—0-010  mm.  in  the  dog,  only  0*008— 0*010  by 
0-007 — 0-009  mm.  in  the  cat,  and  0-008 — 0-012  by  0*006 — 0-008  mm. 
in  the  pole-cat. 

'  Stiles,  Ch.  W.,  "  Notes  on  paras.,"  No.  n  (Journ.  of   Comp.  Med.  and  Vet.  Arch., 
1892,  xiii.,  p.   517). 
6 


82 


THE    ANIMAL    PARASITES    OF    MAN 


Coccidium  bigeminum  appears  to  occur  also  in  man,  at  all 
events  Virchow  published  a  case  which  was  communicated  to  him 
by  Kjellberg,  and  attributes  the  disturbance  to  this  parasite  (Arch, 
f.  path.  An.,  1860,  xviii.,  p.  523).  Possibly  also  it  would  be  more 
correct  to  ascribe  the  observation  of  Railliet  and  Lucet,  which 
is  mentioned  under  Coccidium  hominis,  to  this  species,  as  the 
coccidia  in  that  case  were  distinguished  by  their  diminutive  size 
(length  0*015  mm.,  breadth  o-oio  mm.).  The  case  communicated 
by  Grunow  may  also  probably  refer  to  Cocc.  bigeminum  (Grunow, 
"  Ein  Fall  von  Protozoen  [CoccidienP]  Erkrankung  des  Darmes  " 
[Arch  /.  exper.  Path,  und  Pharm.,  1901,  xlv.,  p.  262]). 


FIG.  34.— Cocci dium  bigeminum,  Stiles  (from  the  intestine  of  a  dog),  (a)  Piece  of 
an  intestinal  villus  beset  with  coccidia,  slightly  enlarged  ;  (b)  Cocc.  bigeminum  (0*015 
mm.  in  diameter),  shortly  before  division  ;  (3)  divided  ;  (d)  each  portion  encysted  ; 
(e)  four  spores  in  each  part,  on  the  left  seen  in  optical  section,  and  a  residual  body — 
strongly  magnified.  (After  Stiles.) 

DOUBTFUL    SPECIES. 

There  are  numerous  reports  in  literature  on  the  occurrence  of  coccidia- 
like  organisms  in  man,  which  are,  however,  open  to  considerable  doubt.  It 
may  prove  useful  to  mention  here  a  few  such  doubtful  forms. 

(i)  Eimeria  hominis,  R.  Blanch.,  1895. — This  is  the  designation  applied 
to  foreign  bodies  found  in  Bordeaux  by  J.  Kiinstler  and  A.  Pitres  in  the 
purulent  pleural  exudation  of  a  man  removed  by  tapping,  The  patient, 
who  had  been  employed  on  a  ship  plying  between  Bordeaux  and  Senegal, 
felt  a  sensation  of  pressure  on  the  left  side  of  the  thorax,  and  suffered 
from  a  dry  cough  and  dyspnoea  :  there  were  neither  night-sweats  nor  fever. 
The  foreign  bodies  consisted  of  nucleated  fusiform  organisms  of  varying  size 
(o'OiS — O'O2O — O'o6o — O'loo  in  length)  and  large  round  or  oval  cysts,  which 
either  contained  the  above-mentioned  little  bodies  exclusively,  or  exhibited, 
in  addition,  an  irregular  residual  body  with  numerous  nuclei.  Further  observa- 
tions could  not  be  made.  Blanchard  regards  the  fusiform  bodies  as  merozoites 
and  the  cysts  as  schizonts  of  a  coccidium  ;  whereas  Moniez  is  of  opinion  that 


COCCIDIUM    BIGEMINUM  83 

they  represent  parts  of  echinorhynchus  (ova  and  floating  ovaries).  (Kiinstler,  J., 
and  Pitres,  A.,  "  Sur  une  psorospermie  trouvee  dans  une  humeur  pleur  "  [Journ. 
d.  microgr.,  1884,  viii.,  p.  469]  *  Blanchard,  R.,  "  Les  Cocc.  et  leur  role  pathog." 
[Caus.  scientif.  soc.  zool.,  France,  1900,^0.  5]  ;  Moniez,  R.,  Trait?  de  parasitol., 
Paris,  1896,  p.  52). 


FIG.  35. — Coccidia   (?)   from   the   pleural   exudation   of  a   man=E?wm'a   hominis, 
R.  Blanch.     (After  Kiinstler.) 


(2)  Coccidioides  immitis  and  Cocc.  pyogenes,  Rixf.  et  Gilchr. — R.  Wernicke 
describes  round  bodies,  with  shells  0*003 — 0*030  mm.  in  diameter,  discovered 
by  his  pupil,  A.  Posada,  to  the  number  of  ten,  in  the  giant  cells  of  granular 
proliferations  situated  in  the  corium.  The  patient,  a  native  Brazilian  soldier, 
exhibited  a  great  many  uneven  protuberances  on  the  skin  of  the  face 
which  were  diagnosed  as  mycosis  fungoides.  In  the  case  of  an  apparently 
identical  cutaneous  disorder  in  a  man,  aged  40,  whose  disease  had  already 
persisted  for  eight  or  nine  years,  Rixford  and  Gilchrist  performed  the 
autopsy  and  found  similar  bodies  not  only  in  the  nodules,  but  in  the 
lungs,  liver,  kidneys,  genitals  and  lymphatic  glands.  They  measured 
O'Oi6 — 0*030  mm.  in  diameter,  and  in  their  developed  state  were  sur- 
rounded by  a  capsule  with  double  outline,  and  had  granular  protoplasmatic 
contents,  but  exhibited  no  nucleus.  The  coccidial  nature  of  these  foreign 
bodies  appears  somewhat  more  probable  from  the  fact  that  the  author 
states  that  he  saw  as  many  as  100  merozoites  in  each  schizont.  In  a  second 
case,  of  a  man,  aged  33,  the  disease  started  with  an  eruption  on  the  forehead  ; 
soon  nodules  appeared  in  the  skin,  and  after  only  two  months  the  lymphatic 
glands  were  affected.  The  patient  died  three  months  after  the  commence- 
ment of  the  disease.  On  examination,  coccidia-like  bodies,  0.020 — 0*035  mm. 
in  diameter,  some  of  which  were  in  the  act  of  schizogony,  were  also  found 
in  the  nodules.  The  authors  consider  that  the  parasites  of  the  one  case 
differ  specifically  from  those  of  the  other  case,  and  therefore  give  them 
different  names  ;  whether,  however,  they  related  to  coccidia  or  sporozoa,  it 
may  be  surmised  that  in  all  three  cases  only  ONE  species  came  under  observa- 
tion. (Wernicke,  R.,  Uber  einen  Protozoenbefund  bei  Myc.  fung.  [C.  f.  B.  u.  P., 


84  THE    ANIMAL    PARASITES    OF    MAN 

1892,  xii.,  p.  859].  Posadas,  A.,  "  Psorospermiosis  infest,  generalizada  "  [In.- 
Diss.,  Buenos- Aires,  1894]  ;"  Ensayo  sobre  una  nuova  neoplasia  del'hombre  .  .  .  " 
Buenos-Aires,  1897—98.  Rixford,  R.,  and  T.  C.  Gilchrist,  "Two  Cases  of 
Protozoan  [Coccidial]  Infection  of  the  Skin  and  other  Organs  "  [Johns  Hopkins 
Hosp.  Rep.,  1897,  i.,  pp.  209,  269,  291]  ;  ref.  in  C.  f.  B.,  P.  u.  I.,  1897,  i,  xxi., 
p.  812.  Also  Blanchard,  R.3  Les  coccid.  et  leur  role  pathog.,  Paris,  1900). 

(3)  An   observation   of    Jurgens   appears    to   me    to   be   still   less   attribut- 
able  to  coccidia.      At   the  autopsy  of  a  patient  who  died  in   the  Charite  in 
Berlin,    greyish-yellow    growths    were    found    on    the    dura     mater    cerebralis 
and  spinalis,  as  well  as  on   the  cauda  equina  ;   the  walls  of   the  calices  and 
renal  pelvis  were   thickened  and  similarly  discoloured,  but  not   those  of  the 
ureters  and  bladder.      In   the   neoplasms,   which  were  but  slightly  vascular, 
various    shining   bodies    were    found,    of   which    some    resembled    myelin    and 
some  starch  grains,  and  some  of  which  had  shells.     A  few  experimental  inocu- 
lations were  undertaken  on  rabbits,  several  of   which  soon  died  from  pleuro- 
pneumonia  ;   one  exhibited  after  four  months  a  rapidly-growing   proliferation 
of   the  left  eye.    At   the  autopsy  of  this  animal,  which  died  a  month  later, 
medullary  tumours  were  found  not  only  in  the  eye  and  orbit,  but  also  in  the 
lungs,  kidneys,  epididymis  and  glands  of  the  mesentery  ;    the  peritoneum  was 
greatly  affected.     The  little  bodies  regarded    as    protozoa    were    not    lacking  ; 
but   in  consequence  of    their  very  diverse  shape   they  can  hardly  be   looked 
upon  as  independent  organisms,  but  they  probably  appertain    to   those    pro- 
ducts of    the    organism  which   frequently  occur    in    proliferations,    and    have 
been  repeatedly   described  as  parasites  (Jurgens,  "  Ueber  Erkrank.  d.  Protoz. 
b.  Menschen."    [Bert.  klin.   Wochenschr.,  1895,   xxxii.,    p.    331]). 

(4)  It  is  advisable   to   mention  here   that   the    "  psorosperm  cysts,"   men- 
tioned in   the  last  edition  of    this  book  (p.   81),   and  which  are  supposed   to 
play   a   part   in    the   diseases   of   the   urethra   and    the   pelvis   of   the   kidney, 
have    been    assigned    to    their    proper    place,    especially    by    Lubarsch    and 
Ribbert  ;    they  are  metarmophoses  of   cells  of  the  epithelial  nests,  which   are 
present  normally,  especially  in  the  urethra  (cf.  Radtke,  E.,  "  Beitr.  z.  Kenntn. 
d.  Uret.  cystica,"  in  Diss.  Kcnigsberg  i.  Pr.,  1900). 

(5)  Seven's   "  Monocystide  Gregarines."     The  pulmonary  parenchyma  of  a 
stillborn    child    was  found  by  Severi   to  be  infiltrated  with  numerous  oval, 
reddish    little    bodies,    the    size    of    which    varied    in    length    between    O'OO3 
and  0-030  mm.,  and  in  breadth  between  o-ooi5   and  0*015   mm.    They  were 
surrounded    by    a    thin    investing    membrane,    and    mostly    lay    free    in    the 
tissue  ;   the  smallest  ones  lay   also   in    the   epithelial   cells   and   in    the   blood- 
vessels.    The   largest  parasites  exhibited   a   granular  plasm,   and  occasionally 
an  eccentrically  situated  nucleus   the  size  of  a  red  blood  corpuscle  (Severi,  A., 
"  Gregarinosi    polmon.    in    Infante    natomorto  "    [Rif.    med.}    1892,    ii.,  p.    54  ; 
Boll.    Accad.    med.    Genova,    1892,    vii.,    No.    2]). 

Order  3.     Hcemosporidia. 

In  the  same  manner  as  our  knowledge  of  the  development  of  the 
coccidia  has  advanced  during  recent  years,  so  the  same  has  occurred  with 
the  Haemosporidia.  The  first  communications  (i)  respecting  the  parasites 
inhabiting  the  blood  or  rather  the  blood  corpuscles  of  vertebrates,  remained 


H-^MOSPORIDIA  85 

unheeded,  although  they  confirmed  the  occurrence  of  foreign  bodies,  com- 
pared by  Lankester  (i)  to  pseudo-navicella  (spores  of  gregarines),  in  the. 
blood  of  amphibia.  It  was  only  after  Gaule  (2)  had  rediscovered  the 
"  little  blood-worms  "  (cytozoa)  that  more  general  attention  was  directed 
to  the  matter,  perhaps  because  of  the  interpretation  given  by  the  author 
to  his  discoveries,  and  they  were  declared  to  be  normal  constituents  of 
animal  cells. 

In  contradiction,  Ray  Lankester  (3)  declared  that  the  cytozoa  were 
of  a  parasitical  nature  and  gave  the  name  of  Drepanidium  ranarum  to 
the  species  observed  in  the  frog,  which  Chaussat1  had  called  Anguillula 
minima.  In  this  case  he  considered  the  parasite  to  represent  a  develop- 
mental stage  of  a  still  unknown  gregarine.  Their  independent  nature  was 
finally  confirmed  by  the  works  of  Danilewsky  (4)  ;  this  investigator  discovered 
analogous  forms  in  the  blood  of  lizards  (Lacerta  viridis  and  L.  agilis)  and 
of  tortoises  (Emys  lutaria\  and  he  described  their  development,  which  takes 
place  in  the  blood. 

Several  years  previously  a  French  military  doctor  in  Constantine,  by 
name  A.  Laveran  (5),  had  observed  hyaline  pigmented  forms  in  the  fresh 
blood  of  malarial  patients-  clinging  to  the  -  red  blood  corpuscles.  On 
noticing  the  appearance  of  "  flagclla  "  on  these  organisms  which  suddenly 
made  lively  movements,  the  thought  occurred  to  him  that  they  were  the 
parasites  (first  termed  Oscillaria  malaria  and  later  Hcejnatozoon  malarice 
of  malaria,  intermittent  fever,  ague).  Although  Richard  (6)  soon  after  con- 
firmed Laverari's  discovery  and  extended  it  by  finding  the  still  unpigmented 
early  stages,  these  communications  were  subjected  to  lively  opposition, 
because  at  this  period  it  was  generally  believed  that  malaria  was  caused 
by  a  bacillus  (Klebs,  Tommasi-Crudelli).  The  investigators  who  afterwards 
pursued  the  subject  (Marchiafava,  Celli,  &c.),  asserted  that  the  objects 
seen  were  merely  evidences  of  degeneration  of  the  red  blood  corpuscles, 
the  haemoglobin  of  which  was  changed  into  melanin  without  the  intervention 
of  a  parasite.  However,  when  Marchiafava  and  Celli  (7)  saw  the  amoeboid 
movements  of  Laveran's  parasites  they  fully  recognised  their  animal  nature. 
The  name  Plasmodium  malarice,  usually  given  to  the  malarial  parasites, 
emanated  from  these  authors,  and  although  unsuitable,  according  to  the  rules 
of  nomenclature,  it  replaces  the  older  and  valueless  term  Oscillaria,  and  is 
still  in  use. 

On  the  abandonment  of  the  opposition  to  Laveran's  doctrine,  numerous 
authors  commenced  a  careful  study  of  the  malarial  parasites,  so  that  by 
the  beginning  of  the  'nineties  certain  conclusions  had  been  arrived  at.  We 
had  learned  to  know  the  difference  of  the  parasites  that  caused  the  various 
forms  of  malaria,  as  well  as  their  development  in  the  blood,  and  confirmed 
the  fact  that  the  blood  of  malarial  patients  inoculated  into  healthy  persons 
produced  in  the  latter  malaria  oi  the  same  type  as  that  from  which  the 
patient  suffered  (Gerhard t  (8)  Bignami  and  Bastainelli  (9)  and  others).  After 
Danilewsky  (10)  discovered  the  occurrence  of  disease-producing  endoglobular 

1  Neither  the  name  of  the  genus  nor  species  can  be  retained,  the  former  because 
already  in  1869  it  was  given  to  an  infusorium  by  Ehrenberg,  and 'the  latter  because 
the  species  had  already  been  named  by  Chaussat  in  1850.  Labbe  has,  therefore, 
given  to  Drepanidium,  Lank.,  the  name  of  Lankesterella  ;  the  correct  designation  of  the 
species  is  therefore  Lankesterella  minima  (Chauss.). 


86  THE   ANIMAL   PARASITES   OF   MAN 

parasites  in  birds,  investigators  directed  their  attention  to  the  study  of  the 
haemosporidia  of  birds,  Grassi  and  Feletti  (n),  Celli  and  Sanfelice  (12),  Kruse 
(13),  Labbe  (14).  The  last-mentioned  author  also  demonstrated  the  existence 
of  analogous  forms  in  reptiles  and  amphibious  animals  in  a  masterly  way. 

Several  authors  gained  great  credit  in  collecting  and  compiling  the 
scattered  and  fragmentary  knowledge  contained  in  a  great  quantity  of  litera- 
ture. Amongst  the  works  of  these  authors  (15),  Mannaberg's  (16),  which 
includes  his  independent  personal  researches,  is  highly  commendable,  as  is 
also  Ziemann's  book  (17).  These  works  should  be  consulted  for  the  literature 
not  mentioned  here. 

The  conclusions  arrived  at,  however,  still  left  many  important  questions 
unanswered.  Nobody  was  in  a  position  to  state  with  any  certainty  in 
what  manner  the  infection  of  man  (apart  from  that  of  animals)  was 
brought  about,  nor  were  there  any  well-grounded  demonstrations  of  how 
the  cause  of  malaria,  according  to  analogy  with  other  parasites,  left  the 
body  of  the  host,  nor  what  was  its  subsequent  fate.  Neither  of  the 
theories  advanced  explain  the  matter  ;  for  even  conceding  the  existence  of 
malarial  germs  in  the  air  and  their  invasion  of  the  human  body  by  way 
of  the  air  passages,  it  remained  an  enigma  why  the  germs  should  only 
occur  at  a  slight  elevation  above  the  soil,  or  should  only  exist  in  certain 
compartments  of  many  houses,  or  why  they  were  not  distributed  in  all 
directions  by  currents  of  air,  &c.,  &c. 

The  last  few  years  have  thrown  light  on  this  subject.  Several  investi- 
gators, working  almost  simultaneously  and  partly  quite  independently,  have 
come  to  the  conclusion  that  blood-sucking  animals  play  a  part  in  malaria. 
For  certain  reasons  a  few  blood-suckers  could  be  rejected  at  once,  others, 
such  as  mosquitoes,  appeared  to  be  particularly  suspicious.1  Manson  (18)  was 
the  first  to  call  attention  to  the  mosquito,  knowing  from  his  own  experience 
the  part  played  by  these  insects  in  the  further  development  of  the  filariae 
of  the  blood  of  man.  Here,  as  in  malaria,  the  mosquitoes  are.  supposed  to 
suck  up  the  parasites  with  the  blood  of  human  beings  and  to  void  them 
ultimately  into  the  water,  so  that  hereby  there  is  at  least  the  possibility  of 
infection  of  other  hosts.  Bignami  (19)  was  of  an  exactly  opposite  opinion 
as  to  the  vole  of  the  mosquito,  which  had  been,  in  Italy,  brought  into  connec- 
tion with  malaria  ages  since,  a  belief  which,  according  to  Koch  (20),  was  also 
shared  by  the  natives  of  Africa.  Supported  by  the  experimental  inoculations 
first  undertaken  and  subsequently  repeated  by  Gerhardt,  Bignami  gave  it 
as  his  opinion  that  mosquitoes  having  themselves  become  infected  by  a  still 
unknown  stage  of  malarial  parasites  occurring  in  the  open,  inoculated  them 
into  man  with  their  bite.  This  opinion,  which  was  supported  by  the  part 
played  by  ticks  (Boophilus  bovis}  •  living  on  cattle  in  the  transmission  of 
the  agent  of  Texas  fever  (Piroplasma  bigeminum},  seemed  to  explain  many 
obscure  points,  but  the  experiments  conducted  by  Bignami  and  Dionisi  to 
substantiate  this  view  gave  negative  results. 

R.    Koch  (20)  combined    the  respective  theories  of  Manson  and   Bignami, 

1  Nuttall,  G.  H.  F.,  "  Die    Mosquito-Malariatheorie  "  (C.  /.  B.,  P.  u.  I.,  1899,  xxv  , 
pp.   161,  209,  245,  285,  and  337). 

2  The  correct  name  of  this  Tick  is  Rhipocephalus  annulatus  (Say).     The  disease  is 
called  Redwater  in  Africa,  and  is  known  by  this  name  in  other  places.     In  Africa  the 
carrier  is  R.  decoloratus  (Koch),  in  Germany  Ixodes  reduvius  acts  as  carrier.     (F.V.T.). 


HiEMOSPORIDIA  87 

and  referred  also  to  the  analogy  of  the  trypanosomiasis  of  cattle  which  is 
transmitted  by  the  tsetse-fly;  nevertheless,  Koch  likewise  could  furnish  na 
proof. 

Ross  (21),  inspired  by  Manson,  first  succeeded  in  following  the  develop- 
ment of  the  plasmodia  that  had  reached  the  stomach  of  the  mosquito 
with  the  blood  of  malarial  patients,  especially  after  he  had  made  Proteo- 
soma  (Hcemoproteus}  living  in  birds  the  subject  of  his  investigations.  He 
found  that  the  proteosoma  in  the  stomach  of  the  mosquito  penetrate  into 
the  intestinal  wall,  grow  into  large  cysts  and  produce  innumerable  rod- 
shaped  spores,  which  are  set  free  in  the  body  cavity  of  the  mosquito  by 
the  bursting  of  the  cysts,  and  then  make  their  -way  into  the  salivary 
glands.  When  Ross  allowed  mosquitoes  to  suck  the  blood  of  infected 
birds,  and  about  nine  days  later  fed  on  healthy  birds  the  infected  mosquito 
that  had  been  kept  isolated,  proteosoma  were  discernible  in  the  blood  of  the 
birds  five  to  nine  days  later. 

These  researches  confirmed  the  mosquito-malaria  theory,  at  all  events 
as  regards  the  malaria  of  birds,  and  its  application  to  human  malaria 
became  more  evident.  At  this  stage  Italian  investigators,  especially  Grassi, 
took  up  the  subject,  and  this  scientist  succeeded  not  only  in  demonstrating 
that  certain  species  of  the  genus  Anopheles,  especially  A.  claviger,  Fabr. 
—  A.  maculipennis,  Meig.,1  inoculate  malaria  to  man  by  means  of  their  bite 
just  like  species  of  the  genus  Culex  are  the  carriers  of  proteosoma  infection 
amongst  birds,  bjit  he  also  followed  the  development  of  the  parasites  in 
the  body  of  the  mosquito  more  carefully  than  had  hitherto  been  done  (22). 
The  commissions-  despatched  for  the  study  of  malaria  on  the  spot  and 
numerous  independent  scientists,  gathered  fresh  knowledge,  so  that  the 
literature  on  the  subject  has  acquired  enormous  dimensions,  notwithstand- 
ing the  short  time  that  has  elapsed  since  the  investigation  of  malaria 
began.  The  researches  as  to  the  structure  and  habits  of  mosquitoes  and 
the  methods  recommended  for  the  prevention  of  malaria  are  continually 
being  extended.  Although  it  is  most  gratifying  to  note  the  large  number 
of  workers  engaged  in  the  solution  of  the  problem  of  malaria,  which  is 
one  of  great  importance  to  mankind,  the  occasional  premature  conclusions 
arrived  at,  and  which  lead  to  the  publication  of  immature  work,  is  to 
be  deplored,  as  they  frequently  mislead  more  sober  investigators. 

After  all  these  works,  the  following  facts  may  be  briefly  stated 
in  regard  to  the  malaria  parasites.  What  had  hitherto  been  known 
of  them  related  to  their  schizogony  and  a  few  erroneously  under- 
stood stages,  which  were  actually  related  to  sporogony  (crescents, 
spheres,  polymitus-form).  By  means  of  their  bite  certain  species 
of  mosquitoes  introduce  the  crescents  and  spheres  into  their  bodies 
with  the  blood.  If  the  atmospheric  temperature  is  sufficiently  high, 
these  forms  become  sexually  differentiated,  and  after  the  females 

1  The  name  claviger  (Fabricius)  used  in  Italy  cannot  stand.  Fabricius  had  no  type 
of  claviger.  (F.  V.  T.). 

3  "  Ergebn.  d.  wiss.  Exped.  d.  Geh.  Rath  Koch  nach  Italien  z.  Erf.  d.  Malaria  "  (Dtsch. 
med.  Wochenschr.,  1899,  p.  69} ;  i.-v.  "  Ber.  ub.  d.  Thatigk.  d.  Malaria-Exp."  (ibid.,  p.  601, 
1900,  Nos.  5,  17,  18,  25,  34,  and  46);  "  Zusammenfass.  Darst.  d.  Ergebn.  d.  Malaria- 
Exp."  (ibid.,  Nos.  49,  50).  Ray,  Annett  and  Austen,  "  Report  on  the  Mai.  Exp.  of 
the  Liverpool  School  of  Tropical  Medicine,'1  Liverpool,  1900. 


50  THE   ANIMAL   PARASITES   OF    MAN 

(macrogametes)  have  been  fertilised  by  the  males  (microgametes) 
they  sporulate.  The  sporozoites  ultimately  collect  in  the  salivary 
glands  of  the  mosquitoes,  and  are  inoculated  into  the  blood  of 
man  or  bird  by  means  of  the  bite  ;  here  they  again  multiply  by 
schizogony  and  thereby  cause  the  disease. 

Accordingly,  certain  species  of  mosquitoes  are  the  definitive  hosts 
of  the  malaria  parasites,  because  the  adult  stage  is  passed  in  them  ; 
and  warm-blooded  animals  are  the  intermediary  hosts. 

Haemosporidia,  in .  addition  to  their  incidence  in  man  and  birds, 
also  occur  in  monkeys  [Kossel  (23)]  and  bats,  [Dionisi  (24)],  the 
alternative  hosts,  however,  of  these  species  are  not  yet  known. 
It  is  doubtful  whether  the  parasites  causing  the  Texas  fever  of 
cattle  (Piroplasma  bigeminum,  Smith),  which  Babes  discovered  and 
on  which  Celli  and  Santori  recently  reported  (C.  /.  B.  P.  u.  /., 
1897,  xxi.,  p.  561),  are  real  Haemosporidia.  According  to  Babes, 
Laveran  and  Nicolle,  analogous  forms  occur  in  sheep  ;  according 
to  Piana,  Galli-Valerio,  Leblanc,  Marchoux,  Nocard  and  Almy, 
they  are  found  in  dogs.  (The  two  last-mentioned  authors,  in 
fact,  suggest  that  -ticks  play  a  part  in  the  piroplasma  infection 
of  dogs),  according  to  Laveran  they  occur  in  horses,  and  according 
to  Lignieres  several  species  of  Piroplasma  live  in  cattle.1 

The  development  of  the  Haemosporidia  of  cold-blooded  animals, 
reptiles,  amphibia  and  fishes,  seemed  amply  known  through  Labbe's 
great  work  (14)  ;  later  works  did  not  with  certainty  disclose  any 
other  circumstances,  though  in  consequence  of  the  discoveries  con- 
cerning the  malaria  parasites  of  warm-blooded  animals  we  began  to 
doubt  the  completeness  of  our  knowledge  of  the  Haemosporidia  of 
cold-blooded  animals.  These  doubts  have  been  fully  justified  by  the 
appearance  of  the  only  book  treating  of  Lankesterella  minima  (  — 
Drepanidium  ranarum)  by  Hintze  (25),  for  in  these  parasites 
there  is  an  alternation  of  generations,  without,  however,  a  change 
of  hosts.  Schizogony  and  sporogony,  according  to  the  author,  go 
on  simultaneously  within  the  same  host,  and  the  oocysts  filled 
with  sporozoites,  which  mature  in  the  intestinal  epithelium  of  the 
host,  make  their  escape  with  the  contents  of  the  intestine  into 
the  open,  whence  they  cause  the  infection  of  other  hosts,  probably 
per  os. 

LITERATURE. 

(i)  CHAUSSAT.     Des  hematozoaires.     These,   Paris,   1850. 

RAY  LANKESTER.    On  Undulina  the  Type  of  a  New  Group  of  Infus.  (Quart. 
Journ.  Micr.  Sc.,   1871,  xi.,  p  387). 

1  Malignant  jaundice  in  dogs  is  due  to  Piroplasma  canis,  carried  by  the  Tick 
Haemophysalis  leachii.  Audouin.  African  coast  fever  in  cattle  is  due  to  Piroplasma 
parvum  (Theiler),  and  is  carried  by  Rhipocephalus  appendiculatus  (Neumann),  and 
/?.  simus  (Koch).  In  horses  and  donkeys  we  get  Piroplasma  equi.  (F.V.T.) 


HLEMOSPORIDIA  89 

OSLER,  W.     An  Account  of    Cert.    Org.   Occurr.  in    the    Liquor    Sanguinis 

(Proc.  Ro\T.  Soc.,  London,   1874,  xxii.,  p.  391). 
BUTSCHLI,  O.     Einige    Bemerk.  iiber  d.  rothen   Blutk.   d.  Frosches  (Abh.  d. 

Senckenb.  nat.  Ges.  Frankf.  a.  M.,  1876,  p.  49). 
LEWIS.     (Quart.  Journ.  Micr.  Sc.,  1879,  xix.,  p.  109). 

(2)  GAULE,   J.    Ueb.    Wiirmchen,  welche  a.  d.  Froschblutkorp.    auswandern  (Arch. 

f.  An.  u.  Phys.,  phys.  Abth.,  1880,  p.   57). 

Die  Beziehungen  d.  Cytozoen  zu  d.  Zellkernen  (ibid.,  1881,  p.  297). 
Kerne,  Nebenkerne  u.  Cytozoen  (Centralbl.  f.  d.  med.  Wiss.,  1881,  p.  561). 

(3)  RAY  LANKESTER.     On  Drep.  ranarum     .     .     .     (Quart.   Journ.  Micr.    Sc.,    1882, 

xxii.,  p.  53). 

(4)  DANILEWSKY,   B.     Die    Haematozoen  d.    Kaltbliiter  (Arch.   f.   mikr.    An.,    1885, 

xxiv.,  p.   588). 

Mater,  pour  servir  a  la  paras,    du    sang  (Arch.   slav.  de  biol.    1886,    i.,  pp. 
89,  364  ;    1887,  ii.,  pp.  33,  157  and  370  ;    Biol.  Centralbl.,  1885,  v.,  p.  529). 

(5)  LAVERAN,  A.     Note  sur  un  nouv.  paras,  trouve  dans  le  sang  de  plus.  mal.  atteints 

de  fievre  pal.  (Bull.  Ac.  med.,  1880,  Nov.  23  and  Dec.  28). 
Nat.  paras,  des  accid.  de  I'impaludisme,  Paris,  1881. 
Des  paras,  du  sane;  dans  1'impalud.  (C.  R.  Ac.  sc.  Paris,  1882,   xcv.,  p.  737). 

(6)  RICHARD,  E.     Sur  le  paras,  de  la  malaria  (C.  R.  Ac.  sc.  Paris,  1882,  20,  ii.). 

(7)  MARCHIAFAVA  and  CELLI.     Fortschr.  d.  Medicin.  1885.  Nos.  n  and  24. 

Nuove   ric.    sulla  inf.  malar.   (Arch.    p.    le   sc.    med.,   1886,   ix.  ;    1888,    xii.  ; 

1889,  xiv.). 
Nouv.  et  sur  1'infect.  mal.  (Arch.  ital.  de  bio.1.,  1887,  viii.,  p.  131). 

(8)  GERHARDT.     Ueber  Intermittens-Impf.  (Zeitschr.  f.  klin.  Med.,  1884,  vii.). 

(9)  BIGNAMI  and  BASTANIELLI.     Stud.  s.  inf.  mal.  (Boll.  R.  Ac.  med.  Roma,  1893-94, 

xx.). 

(10)  DANILEWSKY,  B.     Zur  Parasitol.  d.  Blutes  (Biol.  Centralbl.,  1885-86,  v.,  p.  529). 
La  parasitol.  comp.  du  sang.,  Charkow,  1889.     (Russ.). 
Developp.   d.  paras,   malariques  dans    les    leucocytes  d.  oiseaux  (Ann.  Tnst. 

Pasteur,   1890,  p.  427). 
Sur  les  microb.  d'infect.  malarique  aigue  et  chron.  chez  les  oiseaux  et  chez 

rhQmme  (ibid.,  p.  753). 

Contrib.  a  1'etud.  de  la  microbiose  malarique  (ibid.,   1891,  p.  758). 
Ueb.  d.  Polymitus  malariae  (C.  f.  B.  u.  P.,  1891,  ix.,  p.  397). 
<;n)  GRASSI,  B.,  and  R.  FELETTI.     Malariaparas.  in  d.  Vogeln  (C.    f.    B.    u.  P..  1891, 

ix.,  pp.   403,  429,  461). 

Weiteres  zur  Malariafrage  (ibid.,  1891,  x.,  pp.  449,  481,  517). 
Contribuz.    allo    stud,    dei    parass. .  malarici    (Atti  Accad.  gioenia    sc.   nat. 

Catania,  1892  [4!,  v.). 

(12)  CELLI,  A.,  and  F.  SANFEI.ICE.      Sui  parass.  d.  globulo    rosso    nel    uomo  e  negli 

anim.  (Ann.   i?tit.   d'knene  esperim.,   Roma.  N.  S.  I.,  1891,   and   Fortschr. 
d.  Med.,  1891,  Nos.  12 — i>). 

(13)  KRUSE,  W.    Ueb.   Blutparas.  (Virchow's  Arch.  f.  path.   An.,    1890,   cxx.,  p.  451, 

and  cxx.,  p.  1359). 

(14)  LABBE,  A.     Rech.  zool.  et  biol.  sur  les    paras   endogl.    du    sang   des   Vertebres 

(Arch.  zool.  exp.  et  gen.,  1894  [3],  ii.,  p.  55). 

(15)  SPENER,  C.,  in  Biol.  Centralbl.,  xi.,  p.  390. 

LAVERAN   in   Report    of    the  XII.  Internat.  Congr.  for  Hyg.-Demogr.,  &c., 

London. 
BARBACCI  in   Centralbl.  f.  allsr.  Path.,  1893,  iii-»  P-  49- 

(16)  MANNABERG,  J.     Die  Malariaparasiten.     Vienna,  1893. 

(17)  ZIEMANN,  H.     Ueb.  Malaria-u.  andere  Blutparas.     Jena,  1898. 

(18)  MANSON,    P.      The    Goulstonian    Lecture   on    the    Life-history   of    the   Malarial 

Germ  outside  the  Human  Body  (The  Lancet,  1896,  i.,  pp.  695,  751,  831). 
Hypotheses  as  to  the  Life-history  of  the  Malarial  Parasite  outside  the  Human 
Body  (ibid.,  1896,  ii.,  p.  1715). 

(19)  BIGNAMI,  A.     Hypotheses  as  to  the  Life-history  of  the  Malarial  Parasite  outside 

the  Human  Body  (The  Lancet,  1896,  ii.,  pp.  1363,   1441). 

(20)  KOCH,  R.     Aerztl.  Beob.  in  d.  Tropen   (Verh.   d.  deutsch.   Colonial-Ges.     Abth. 

Berlin-Charlottenberg,  1897-98.     No.  7,  p.  280). 
Reiseberichte  iiber  Rinderpest.     Berlin,  1898. 

(21)  Ross,  R.     On  some  Peculiar  Pigmented  Cells  found  in  Two  Mosquitoes  Fed  on 

Malarial  Blood  (Brit.  Med.  Journ.,  1897,  ii.,  p.  1786). 
The  Role  of  the  Mosquito   in  the   Evolution   of   the   Malaria   Parasite   (The 

Lancet,  1898,  ii.,  p.  488). 
Report  on  the  Cultivation  of  Proteosoma  in  Grey  Mosquitoes.    Calcutta,  1898. 


90  THE   ANIMAL   PARASITES   OF   MAN 

(22)  GRASSI,   B.     Several  Notes  In   the  Rendic.   R.  Ace.   Lincei.   Roma,   Ser.  5,  vols, 

vii.  and  viii.,   1898. 

Le  recente  scoperte  sulla  malaria  esposte  in  forma  popolare.     Milano,  1899. 

Studi  di  un  zoologo  sulla  malaria  (Atti  R.  Ace.  Lincei.  Mem.  Cl.  sc.  fis.  Ser.  5, 
vol.  iii.,  Ann.  ccxcvi.,  1900)  ;  in  2nd  edition,  Rome,  1901  ;  translated 
into  German  and  entitled  Die  Malaria,  Stud,  eines  Zool.  ist  edition, 
Jena,  1900;  2nd  edition,  Jena,  1901. 

BASTIANELLI,  BIGNAMI,  CELLI,  DIONTSI  and  others  either  participated  in 
Grassi's  labours  or  worked  independently  ;  the  works  of  these  authors 
appeared  partly  in  the  Rendic.  R.  Ace.  Lincei,  Roma,  partly  in  the  "  Atti 
soc.  per  gli.  stud,  della  malaria,"  and  partly  independently. 

(23)  KOSSEL,    H.     Ueber   ein.    malariaahnl.    Blutparas.    bei  Affen  (Zeitschr.    f.   Hyg. 

u.  Inf.,  1899,  xxxii.,  p.  25). 

(24)  DIONISI,  A.     La  Malaria  di  alcune  specie  di    pipistrelli    (Ann.  d'igiene  sperim, 

N.  S.,  ix.,  1899). 

(25)  HINTZE,   R.     Lebensweise  u.   Entw.  d.  Lankesterella  minima  (Zool.    Jahrb.  An., 

1902,  part  xv.,  p.  693  ;    also  during  the  In.-Diss,  Berlin,  1901. 


THE  H^MOSPORIDIA  OF  MAN. 

The  disease  induced  in  man  by  Haemosporidia  (MALARIA,  INTER- 
MITTENT FEVER,  AGUE  OR  CHILL-FEVER)  is,  apart  from  waterless 
deserts  and  the  polar  regions,  distributed  over  the  entire  surface 
of  the  globe,  but  not  equally,  and  it  appears  in  various  forms. 
The  rhythmical  course  of  the  fever  is  characteristic  ;  it  sets  in 
suddenly  with  a  sensation  of  cold  or  with  a  rigor,  in  a  few  hours 
the  temperature  rises  to  40  or  41°  C.,  and  remains  at  this  for 
some  hours,  during  which  time  the  patient  himself  feels  the  increased 
bodily  temperature  (dry  tongue,  heat,  headache)  ;  then  the  tem- 
perature falls  rapidly,  often  to  below  normal,  accompanied  by 
profuse  perspiration.  There  is,  moreover,  sensitiveness  to  pressure 
in  the  region  of  the  spleen,  and  the  spleen  itself  is  enlarged. 
After  the  attack,  the  patient  feels  somewhat  languid,  but  other- 
wise he  is  quite  well  until  another  attack  supervenes.  The  attacks 
may  recur  daily  (febris  quotidiana),  or  one  day  may  be  free  (febris 
tertiana),  or  two  days  may  elapse  between  the  attacks  (febris  quar- 
tana)  ;  thus  the  fever  appears  only  on  the  third,  fifth  and  seventh 
day,  or  the  fourth,  seventh,  tenth  day,  and  so  on,  respectively. 
Two  types  of  tertian  fever  are  clinically  differentiated  :  the  mild 
"  spring  tertian  fever "  that  appears  in  the  spring,  and  the 
severe  "  sestivo-autumnal  fever,"  which  is  identical  with  "  tropical 
malaria."  This  fever  is  also  termed  the  malignant  or  pernicious 
form,  because  its  paroxysms  being  protracted  approach  each  other 
more,  and  thus  give  rise  to  a  continuous  or  subcontinuous  fever. 
Not  infrequently  combinations  occur  ;  we  thus  hear  of  febris  ter- 
tiana duplex,  when  the  attacks  certainly  occur  daily,  but  are  dis- 
tinguished from  one  another  either  by  the  different  time  at  which 
they  commence,  or  by  different  duration,  different  degree  of  the 


I2I2I2I2.. 


THE    HvEMOSPORIDIA   OF   MAN  QI 

fever,  &c.  The  paroxysm  of  the  first  day  with  the  same  pecu- 
liarities then  sets  in  only  on  the  third  and  fifth  days ;  the 
paroxysm  of  the  second  day  is  repeated  only  on  the  fourth  and 
sixth  days,  and  so  on.  In  a  similar  manner  two  or  three  quartan 
fevers  may  combine,  and  there  may  be  a  febris  quart  ana  duplex 
or  triplex. 

In  order  to  demonstrate  the  combinations  of  analogous  fevers 
the  following  table,  taken  from  Mannaberg's  work,  may  prove 
useful  : — 

—  Febris  quotidiana  simplex. 
=  F.  tertiana  simplex. 
=  F.  quart  ana  simplex. 
=  F.  tertiana  duplex. 

123123123      ..          ..      =  F.  quartana  triplex. 
120120120..          ..      =  F.  quartana  duplex. 

The  equivalent  figures  connected  by  brackets  represent  the  separate 
paroxysms  of  fever,  whilst  the  o  represents  the  afebrile  day. 

It  has  not  yet  been  quite  determined  whether  the  so-called 
BLACKWATER  FEVER  belongs  to  the  group  of  malarial  fevers,  but 
according  to  Plehn's  statements  this  appears  to  be  the  case,  as, 
at  all  events  at  the  commencement  of  the  disorder,  Haemosporidia 
are  met  with  in  most  of  the  cases  :  they  certainly,  however,  dis- 
appear very  soon,  in  consequence  of  the  enormous  disintegration 
of  blood  corpuscles  that  takes  place  in  this  disease. 

Finally,  we  speak  of  "  MASKED  FORMS  of  malaria  "  when  there 
are  disturbances  of  the  general  health  that  have  a  periodical 
character  and  yield  to  quinine.  Nevertheless,  only  those  cases 
should  be  reckoned  as  malaria  the  diagnosis  of  which  is  confirmed 
by  the  examination  of  the  blood,  i.e.,  by  the  discovery  of  Haemo- 
sporidia. 

Different  Haemosporidia  correspond  to  the  different  types  of 
malaria,  and  may  be  regarded  either  as  varieties  of  one  species 
or  as  distinct  species  ; l  the  latter  view  appears  to  be  in  accordance 
with  the  present  condition  of  our  knowledge. 

1  In  addition  to  the  literature  mentioned  above,  the  following  may  be  cited  : 
Golgi,  C.(  "  Sull'  inf.  malar."  (Arch.  p.  le.  sc.  med.,  1886,  x.,  p.  104);  "  Ancora  sull 
inf.  mal."  (Gaz.  d.  ospid.,  1886,  No.  53)  ;  "  Sul  ciclo  evelutivo  dei  par.  mat.  .  .  ." 
Arch.  p.  le  sc.  med.,  1889,  xiii.,  p.  173,  and  Fortschr.  der  Med.,  1889,  No.  3)  ;  Mar- 


92  THE   ANIMAL    PARASITES    OF   MAN 

i.  Plasmodium  malarice  (Laveran). 

Syn.  :  Oscillaria  malaria,  Laveran,  1883  ;  Plasmodium,  var.  quartana, 
Golgi,  1890  ;  Hcemamceba  malaria,  Grass!  and  Feletti,  1892  ;  Hamamceba 
laverani,  var.  quartana,  Labbe,  1894;  Plasmodium  malaria  quartanum,  Labbe, 
1899. 

This  species  is  the  cause  of  quartan  fever,  and  is  therefore  also 
frequently  termed  the  QUARTAN  PARASITE.  Soon  after  the  paroxysm 
a  small  unpigmented  body  with  sluggish  amoeboid  movement  is 
found  on  the  red  blood  corpuscles.  Whilst  gradually  growing  the 
parasite  penetrates  within  the  blood  corpuscle,  and  about  twenty- 
four  hours  after  the  attack  it  commences  to  form  the  first  fairly 
coarse  grains  of  melanin,  which  are  mostly  situated  at  the  periphery. 
As  the  pigment  increases  and  the  parasite  grows — forty-eight  hours 
after  the  attack  it  measures  from  one-half  to  two-thirds  the  size 
of  the  blood  corpuscle — the  movements  become  more  sluggish  and 
are  finally  entirely  arrested.  Sixty  hours  after  the  first  paroxysm 
and  twelve  hours  before  the  next  one  the  plasmodia,  which 
resemble  discs,  completely  fill  the  blood  corpuscles  and  only  a 


FIG.   36. — The  development  of  the  quartan  parasite  in  the  red  blood  corpuscles 
of  man.     (After  Mannaberg  or  Golgi). 

• 

narrow  rim  is  left,  which  later  on  also  disappears.  Schizogony 
then  commences  (six  hours  before  the  paroxysm)  ;  the  grains  of 
melanin  are  arranged  radially,  and  then  all  crowd  towards  the 
centre  of  the  disc,  the  peripheral  part  of  which  thereby  becomes 
pigmentless,  and  one  observes  a  spoke-like  design,  which  indicates 
the  radial  segmentation  of  the  disc ;  this  becomes  more  and 
more  distinct  and  finally  leads  to  the  segmentation  of  nine  to 
twelve  pear-shaped  bodies  placed  wheel-like — the  merozoites.  These 
finally  separate  from  the  central  heap  of  melanin  and  from  each 
other,  and  by  attacking  fresh  blood  corpuscles  induce  the  subsequent 
paroxysm  of  fever.  The  melanin  grains  are  taken  up  by  the 
leucocytes  and  are  mostly  deposited  in  the  spleen,  though  also 

chiafava  and  Bignami,  "La  quotid.  e  la  terz.  est.-aut."  (Rif.  med.,  1891,  No.  217)  ;  "  Le 
febre  mal.  est.-aut."  (Boll.  R.  Ace.  med.  Roma,  1892,  xvii  ;  Dtsch.  med  Wochenschr., 
1892,  No.  51.  Grassi  and  Feletti,  "  Contrib.  allo  stud.  d.  par.  mal."  (Atti  Ace.  Gioen. 
Catania,  1892  [4],  v.,  p.  i  ;  Bastianelli  and  Bignami,  "  Sulla  strutt.  d.  par.  mal.  .  .  ." 
(Atti  soc.  stud.  d.  mal.,  1899,  i.).  Further  literature  by  Mannaberg;  Grassi,  Celli,  Labbe, 
Liihe,  Ziemann,  &c. 


PLASMODIUM    VIVAX  93 

sometimes  in  the  bone  marrow,  &c.  ;  this  is  therefore  the  cause, 
of  the  well-known  pigmentation  of  the  spleen  in  persons  who  have 
suffered  from  malaria. 

The  entire  increase  by  schizogony  takes  place  in  the  circulating 
blood  and  occupies  seventy-two  hours.  The  blood  corpuscles 
attacked  become  neither  enlarged  nor  pale.  If  suitable  methods 
for  staining  are  used  one  succeeds  in  demonstrating  in  all  stages 
the  nucleus  in  the  plasmodium  as  well  as  the  stages  of  segmenta- 
tion of  the  nucleus  in  schizogony. 

It  is  very  seldom  that  in  examining  the  blood  of  persons 
suffering  from  quartan  fever  one  comes  across  other  forms  (spheres, 
polymitus). 

The  appearance  of  quartana  duplex  or  triplex  is  explained 
by  the  circumstance  that  two  or  three  generations  of  parasites, 
with  a  difference  of  twenty-four  hours  in  their  development,  are 
present  in  the  blood.  Irregularities  in  the  duration  of  the 
development  of  the  parasites  obscure  the  regular  character  of  the 
disease. 


2.  Plasmodium  vivax  (Grassi  and  FeL). 

Syn  .  :     Hcemamceba   vivax,   Gr.   et   FeL,    1892  ;  Plasmodium,  var.  tertiana, 
Golgi,  1889  ;   Hcemamceba   Laverani,   var.   tertiana,  Labbe,  1894  ;   Plasmodium 
tertianum,  Labbe,  1899. 


This  species  is  the  cause  of  spring  tertian  fever  ;  it  is  distin- 
guished from  Plasmodium  malarice  first,  by  the  shorter  period 
(forty-eight  hours)  occupied  in  schizogony  ;  secondly,  by  the  greater 
activity  of  the  amoeboid  movements  which  do  not  even  cease  on 
being  exposed  to  room  temperature,  and  by  the  fact  that  many 
of  the  melanin-bearing  stages  are  visible  ;  moreover,  the  affected 
blood  corpuscles  become  enlarged  and  lose  their  colour.1  The  stages 
of  schizogony  are  rarely  found  in  the  circulating  blood,  but  fre- 
quently occur  in  the  spleen.  During  the  process  there  is  no  wheel- 
like  arrangement  of  the  merozoites,  which  lie  in  a  roundish  heap 
about  the  pigment  residue  ;  they  are  smaller  than  those  of  Plas- 
modium malaria  and  are  fifteen  to  twenty  in  number.  The  spheres 
that  come  under  observation  in  this  type  attain  a  size  double  that 
of  a  red  blood  corpuscle,  and  are  plentifully  supplied  with  coarse 

1  On  staining  according  to  Romanowsky's  method  a  peculiar  stippling  of  the 
affected  blood  corpuscles  appears  (Schiiffner,  Deutsch.  Arch.  /.  kl.  Med.,  1899,  Ixiv.. 
p.  428;  Maurer,  C.  f.  B.,  P.^ii  /.,  1900,  xxviii.,  p.  n_i). 


94  THE    ANIMAL    PARASITES    OF    MAN 

and  even  rod-shaped  pigment  granules,  which  are  actively  turmoiled. 
The  polymitus  form  may  be  observed  in  the  moist  chamber. 

Irregularities  sometimes  occur  also  in  the  schizogony  of  this 
species.  The  occurrence  of  two  generations  separated  by  about 
twenty-four  hours  brings  about  tertiana  duplex. 


FIG.  37. — The  development  of  the  tertian  parasite  in  the  red  blood  corpuscles  of 
man  ;  to  the  right  a  "  polymitus."  (After  Mannaberg.) 

3.  Plasmodium,  sp.1 

Syn.  :    Laverania  malarice,    Gr.  and  Fel.,    1890;    Hcemamceba  malarice  prcecox 
Grassi  and  Feletti,  1892,  nee.  Hcem.  pvcecox,  Gr.  and  Fel.,  1890. 

This  parasite  is  the  cause  of  aestivo-autumnal  or  tropical  fever  (also 
termed  febris  perniciosa  s.  maligna,  tertiana  maligna,  febris  tropica, 
febris  bidua,  also  febris  quotidiana).  The  parasite  is  very  small  and 
at  most  only  occupies  the  third  part  of  a  blood  corpuscle  ;  it  is, 
moreover,  very  active ;  its  pigment  is  very  finely  granular  ;  very 
frequently  also,  at  all  events  more  frequently  than  in  other  plasmodia, 
it  assumes  an  annular  form,  the  bodily  substance  in  the  centre 
becoming  attenuated  and  finally  tearing  through.  The  develop- 
ment by  schizogony  normally  occupies  a  period  of  forty — eighty 
hours,  but  the  corresponding  stages  are  seldom  seen  in  the  peri- 

1  The  correct  terminology  of  this  species  is  still  unsettled.  Grassi  and  Feletti  have 
certainly  called  it  Laverania  malaria,  but  I  see  no  reason  that  a  particular  species 
should  be  set  up.  Besides,  this  species  belongs  to  the  genus  Plasmodium.  Within 
this  genus  there  already  exists  a  species,  "  malariae  "  (Laveran),  the  quartan  parasite, 
and  consequently  the  Grassi-Feletti  denomination  of  species  cannot  again  be  used  in 
the  same  genus.  For  this  reason  other  authors,  such  as  Doflein,  use  the  special  term 
of  "praecox,"  which  also  originates  from  Grassi  and  Feletti,  combined  with  H&mamoeba. 
But  in  the  same  work  (Boll.  mens.  Accad.  Gicenia  sc.  nat.  Catania,  1890,  and  C.  f.  B. 
u.  P.,  1891,  ix.)  they  term  Hcemamceba  pr&cox  a  haemosporidium  of  birds  and  one  of 
man.  As  the  identity,  however,  of  these  forms  has  not  been  proved,  and  is  not 
even  probable,  the  term  Heemamceba  prcecox  can  only  be  applied  to  one  or  the  other, 
and  should  hold  good  for  the  haemosporidium  of  birds  as  being  the  first  mentioned  in 
the  text.  Neveu  Lemaire  (Les  h6maioz.  du  paludisme,  Pajis,  1901)  uses  the  most  prac- 
tical term,  i.e.,  H&matozoon  falciparum,  Welch. 


THE   SPOROGONY    OF   THE    MALARIA    PLASMODIA  95 

pheral  blood  as  they  are  gone  through  in  the  spleen,  liver,  bone- 
marrow  and  cerebral  capillaries.  The  latter,  indeed,  are  frequently 
crowded  with  plasmodia  undergoing  schizogony,  thereby  explaining 
the  severe  cerebral  symptoms.  The  number  of  small  merozoites, 
arranged  spoke-like,  average  from  seven  to  twelve,  rarely  more. 

In  this  type  of  fever,  Laveran's  sickles  or  so-called  crescents,  are 
more  frequently  met  with  than  in  other  fevers. 


FIG.  38 — The  "  pernicious  para-  FIG.   39.— The  crescents  (Laverania)  of  the 

site  "  in  the  red  blood  corpuscles  pernicious  parasite.     (After  Mannaberg). 

of  man.     (After  Mannaberg.) 

4.  DOUBTFUL  SPECIES. 

The  independence  of  the  three  foregoing  species  that  are  distinguished  one 
from  the  other  by  their  morphological  and  biological  characteristics,  has  also 
been  proved  by  the  results  obtained  after  inoculation  of  the  blood  of  malaria 
patients  into  healthy  persons  ;  this  can  even  be  accomplished  with  very  small 
quantities.  After  varying  periods  those  inoculated  always  acquire  malaria 
which  is  of  the  same  type  as  that  of  the  case  from  which  the  blood  is 
taken. 

According  to  Celli,1  and  in  opposition  to  the  views  of  many  authors, 
an  actual  quotidian  fever  occurs  in  summer  and  autumn,  the  agent  of 
which  is  closely  related  to  the  Plasmodium  of  Tropical  fever.  The  quotidian 
parasite  is,  however,  smaller,  has  granules  of  pigment  that  are  scarcely  per- 
ceptible, and  completes  its  cycle  of  development  in  the  blood  in  twenty-four 
hours.  Another  very  rare  form  has  been  observed  by  Celli  and  Marchiafava 
in  Italy,  and  by  Marchoux  in  the  Tropics ;  it  develops  in  less  than  twenty- 
four  hours,  without  transforming  the  haemoglobin  into  melanin.  The  inde- 
pendence of  these  two  forms  is  questionable  ;  they  are  mostly  regarded  as 
varieties  of  the  plasmodia  of  tropical  fever.2 

5.  THE  SPOROGONY  OF  THE  MALARIA  PLASMODIA. 

Forms  have  already  been  mentioned  in  the  above  description 
of  the  malaria  parasites  of  man  that  are  incidentally  met  with, 
besides  the  stages  of  schizogony  ;  these  are  the  so-called  SPHERES 
and  CRESCENTS,  or  SICKLES  (fig.  39).  They  were  found  in  blood  just 


1  Celli,  A.,  Die  Malaria  nach  den  neuesten  Forsch.,  translated  by  Kerschbaumer, 
Berlin,  Vienna,  1900  (Celli,  A.,  La  malaria  sec.  le  nuove  ricerche.,  2nd  edition,  Rome,  1900). 

'2  The  same  may  hold  good  for  Laverania  limnhtmica,  the  malaria  parasite  of  the 
Cubans  (Coronado,  O.  V.,  in  Crdnica  med  quir.  de  la  Habana,  1897,  No-  6  '•  and  c-  / 
B.,  P.  u.  /.,  1897,  xxii.,  p.  558). 


96  THE   ANIMAL   PARASITES   OF   MAN 

extracted  from  the  body,  not,  however,  in  entirely  fresh  cases, 
but  only  after  the  illness  has  persisted  for  several  days.  Expe- 
rience has  also  demonstrated  that  the  crescents,  which*  are  only 
observed  in  malignant  tertian  fever,  increase  greatly  if  the  disease 
is  of  long  duration,  and  finally  are  the  only  forms  present  ;  they  also 
do  not  retain  their  shape,  but  become  shortened  to  ovals,  and  at 
last  become  spheres.  This  process  can  be  regularly  induced  by 
the  addition  of  distilled  water  [Marshall  (i)],  or  by  breathing  on  the 
slide  [Manson  (2)].  Frequently  also  one  may  observe  that  some 
of  the  spheres  (in  abstracted  blood)  develop  "  flagella "  that 
actively  lash  about  and  thus  become  the  "  polymitus  "  :  the  fla- 
gella detach  themselves,  leaving  behind  an  immovable  lump  of 
protoplasm  with  grains  of  melanin. 

As  all  these  processes  were  found  to  take  place  outside  the  cir- 
culating blood  and  to  lead  to  final  disintegration,  and  as  nuclei  were 
not  visible,  most  investigators  regarded  the  spheres,  sickles  and  poly- 
mites  as  forms  of  degeneration  of  the  malaria  parasites.  Only 
Mannaberg  (3)  stated  that  having  seen  indications  of  the  union 
of  two  crescents  he  regarded  these  at  any  rate  as  representing 
conjugation  forms. 

The  assumption  of  the  absence  of  the  nucleus  was,  however, 
erroneous.  Sacharoff  (4)  first  demonstrated  the  nucleus  in  spheres 
from  the  blood  of  crows,  and  also  showed  that  the  entire  nuclear 
substance  passes  into  the  flagella  when  polymitus  formation  takes 
place.  The  experiments  also  undertaken  by  Ross  on  Hanson's 
suggestion  were  very  important  ;  they  demonstrated  that  crescents 
sucked  up  by  mosquitoes  from  the  blood  of  a  man  soon  turned 
to  spheres  in  the  stomach,  and  about  half  of  them  were  trans- 
formed into  polymites.  MacCallum  (5)  recognised  the  significance  of 
the  "flagella"  in  the  Haemosporidia  of  crows;  he,  like  Opie(6) 
before  him,  found  that  there  were  two  kinds  of  spheres,  one  kind 
with  a  coarsely  granular  protoplasm  which  became  a  vivid  blue 
when  stained  with  methylene  blue,  the  other  hyaline  and  scarcely 
stainable  :  the  latter  only  becoming  polymites.  He  observed 
that  the  actively  moving  flagella  which  detached  themselves 
penetrated  into  the  coarsely  granular  spheres,  and  thus  the 
enigma  was  solved.  The  "  flagella "  whose  origin  and  composi- 
tion Bignami  and  Bastianelli  (7)  had  traced  in  the  plasmodium  of 
the  aestivo-autumnal  fever  are,  accordingly,  microgametes  ;  the 
spheres  are  partly  macrogametes,  partly,  so  far  as  they  become 
polymites,  microgametocytes  ;  and  the  polymitus  is  a  microgameto- 
cyte  at  the  moment  of  the  development  of  the  microgametes. 


THE  SPOROGONY  OF  THE  MALARIAL  PLASMODIA         97 

Numerous  works  then  followed,  mostly  relating  to  the  sporu- 
lation  of  the  plasmodium  which  takes  place  in  the  body  of  the 
mosquito1  (Ross,  "  The  Proteosoma  of  Birds  in  Species  of  Culex  "  ; 
Grassi,  "The  Plasmodia  of  Man  in  Species  of  Anopheles  "  ;  Bignami 
and  Bastianelli  (8),  "  The  Tertian  Parasites" ;  also  Koch  and  others). 
Schaudinn(io)  pointed  out  the  analogy  with  the  development  of  the 
coccidia. 

Schizonts  alone  are  found  in  the  blood  of  malaria  patients  in 
fresh  infections.  It  is  only  after  a  certain  time  that,  in  addition, 
the  gametes  (crescents,  sickles,  or  spheres)  appear  in  gradually 
increasing  numbers.  The  difference  between  male  and  female 
individuals  (microgametocytes  and  macrogametes)  in  the  plasmodia 
of  human  malaria  is  not  so  great  as  is  the  case  in  the  proteo- 
soma  of  birds  or  in  the  coccidia. 


a.  b,  c.  d. 

FIG.  40. — Stages  of  development  of  the  pernicious  parasites  in  the  intestine  of 
Anopheles  maculipennis  (after  Grassi).  (a)  Macrogamete  (crescent)  still  clinging  to  the 
human  blood  corpuscle ;  (b)  macrogamete  (sphere)  half  an  hour  after  the  mosquito  has 
sucked  ;  (c)  microgametocyte  (crescent  adhering  to  the  blood  corpuscle)  ;  (d)  micro- 
gametocyte  (sphere)  half  an  hour  after  sucking  (the  nucleus  is  broken  up) ;  (e) 
microgamete  attached  to  the  residual  body  (polymitus  stage). 

When  conveyed  into  the  intestine  of  Anopheles  they  mature 
rapidly,  and  the  filamentous  microgametes,  which  are  chiefly 
composed  of  nuclear  substance,  but  have  no  flagella,  penetrate 
into  the  macrogametes  which,  shortly  before,  have  reduced  their 
nucleus.  The  copula  thus  formed  is  not  immediately  transformed 
into  an  oocyst  as  is  the  case  with  the  coccidia,  but  first  becomes 
a  motile  fusiform  body  ("  vermicule,"  Danilewsky,  "  ookinet," 
Schaudinn,  fig.  41),  which  bores  actively  into  the  intestinal  wall 
of  the  mosquito's  stomach,  where  it  settles.  A  very  delicate 
integument,  which  is  probably  a  product  of  the  host,  then  develops 
on  the  surface  of  the  ookinet,  which  becomes  round,  and  the 
oocyst  is  thus  formed.  The  number  of  parasites  in  one  mosquito 
may  be  very  considerable.  As  they  become  gradually  larger  they 
project  like  protuberances  beyond  the  outer  surface  of  the  pos- 
terior mid-gut,  which  is  greatly  dilated  (fig.  42). 

1  For  the  classification,  structure  and  life  history  of  mosquitoes,  see  The  Diptera. 
7 


98 


THE   ANIMAL   PARASITES    OF   MAN 


The  development  of  the  sporonts  in  mosquitoes  (of  the  genus 
Anopheles)  is  dependent  on  the  atmospheric  temperature  and  the 
species  of  parasite.  The  plasmodium  of  the  malignant  tertian 
(tropical  fever)  completes  its  development  within  eight  days  at  a 
temperature  of  28 — 30°  C. ;  below  18°  C.  the  development  ceases. 
The  same  condition  also  holds  good  for  Plasmodium  vivax,  whereas 
Plasmodium  malarice  requires  a  lower  temperature,  that  is  to  say, 
it  will  still  develop  at  i6'5°  C.,  but  not  if  the  temperature  is 
over  30°  C. 


. 


FIG.  41. — Ookinets  of  pernicious  parasites 
in  the  stomach  of  Anopheles  maculipennis 
thirty- two  hours  after  having  been  sucked  in. 
(After  Grassi.) 


FIG.  42. — Transverse  section  of 
the  stomach  of  an  Anopheles,  with 
cysts  of  the  pernicious  parasites. 
(After  Grassi.) 


The  oocysts  resting  in  the  intestinal  wall  are  at  first  oval, 
but  with  their  further  growth  they  become  globular.  First  of 
all  the  nucleus  within  them  divides  up  into  a  large  number  of 
daughter  nuclei.  A  portion  of  protoplasm  gathers  round  each  one 
of  these  nuclei,  and  thus  a  number  of  mononuclear  polyhedric  cells 
are  formed  and  connected  one  with  the  other  by  bridges  of  proto- 
plasm which  occupy  the  entire  internal  space  of  the  cystic  mem- 
brane (fig.  43,  a).  These  cells  may  be  termed  sporoblasts,  but 
contrary  to  the  similarly  termed  forms  in  coccidia,  they  remain 
naked  and  immediately  form  the  sporozoites.  This  process  begins 
by  a  division  of  the  nucleus  in  each  sporoblast  ;  the  numerous 
daughter  nuclei  take  up  a  peripheral  position  in  the  plasma  of 
the  sporoblasts  and  receive  a  thin  coating  of  hyaline  proto- 
plasm. The  entire  substance  of  the  sporoblast  is  not,  however, 
consumed  thereby ;  the  larger  part  remains  undivided,  becomes 
elongated  and  granular ;  it  represents  a  residual  body  which  is 
surrounded  by  numerous  roundish  sporozoites  (fig.  43,  b  and  c). 
The  sporozoites  soon  become  small,  elongated  forms  pointed  at 
both  ends,  one  of  which  still  adheres  to  the  residual  body.  The 


THE  SPOROGONY  OF  THE  MALARIAL  PLASMODIA         99 

separation  of  the  sporoblasts  is  never  complete,  and  thus  it  may. 
happen  that  the  residual  bodies  remain  more  or  less  connected 
together  for  a  long  time.  It  is  only  when  the  sporozoites  are 
quite  mature  that  a  separation  takes  place  ;  then  the  sporozoites, 
which  are  about  0*014  mm.  in  length  and  are  provided  with  an 
elongated  nucleus,  become  detached  from  the  residual  body  (fig.  43,  d). 
The  size  attained  by  the  mature  oocysts  fluctuates  between 
0*03 — 0*09  mm.  ;  on  an  average,  however,  they  seldom  exceed 
0*06  mm.  The  number  of  sporozoites  in  each  oocyst  varies  to  a 
much  greater  extent  (between  a  few  hundreds  and  over  10,000). 


FIG.  43. — Four  different  stages  of  sporulation  of  malaria  parasites  from  Anopheles 
maculipennis,  strongly  magnified,  (a — c)  The  pernicious  parasite  ;  (a)  four  to  four  and 
a  half  days  after  ingestion  ;  (b  and  c)  five  to  six  days  after  ingestion  ;  (d)  tertian  para- 
sites, eight  days  after  ingestion.  (After  Grassi.) 

According  to  all  appearances  the  mature  oocysts  burst  spon- 
taneously and  discharge  their  sporozoites  into  the  body  cavity  of 
the  host.  Here  they  are  distributed  by  the  circulation  of  the  blood, 
and  after  a  few  hours  they  already  accumulate  within  tie  salivary 
glands.  It  has  not  been  ascertained  whether  they  penetrate  actively 
or  are  drawn  in  by  chemical  action.  In  any  case,  according  to 
Grassi  and  Ruge  (10)  they  possess  specific  movements  which  hardly 
differ  from  those  of  the  sporozoites  of  coccidia,  but  are  only  observable 
when  the  atmospheric  temperature  is  rather  high. 

During  the  process  of  puncture  by  the  mosquitoes  the  sporo- 
zoites are  introduced  into  the  wound  with  the  saliva,  and  by 
this  means  man  becomes  infected,  as  has  been  proved  by  experi- 


IOO 


THE    ANIMAL  PARASITES   OF    MAN 


merit.  It  may  be  assumed  that  they  are  transformed  directly 
into  the  amoeboid  form  of  the  Hsemosporidia,  and  multiply  by 
schizogony  until  their  number  is  sufficiently  great  to  produce  the 
first  paroxysm  of  fever.  If  a  small  number  only  happen  to  be 
present  in  the  salivary  glands  of  the  mosquito  they  are  all  dis- 
charged with  its  first  bite  ;  in  other  cases  only  a  few  are  got  rid 
of,  so  that  under  these  circumstances  one  single  Anopheles  is 
capable  of  infecting  several  persons.  The  same  mosquito  also 
may  repeatedly  take  up  malarial  plasmodia  from  sick  persons,  and 
thus  may  harbour  simultaneously  different  stages  of  development, 
and  thus  repeatedly  replenish  its  salivary  glands  with  sporozoites. 


FIG.  44. — Section  through  a  tubule  of  the.  sail  vary  gland  of  an  Anopheles,  with  sporo- 
zoits  of  the  pernicious  parasites  ;  above  an  isolated  sporozoit  with  higher  magnification. 
(After  Grassi.) 


Research  has  demonstrated  that :  THE  MALARIAL  PARASITES  OF 

MAN  UNDERGO  AN  ALTERNATION  OF  GENERATIONS  AND  REQUIRE 
TWO  DIFFERENT  HOSTS  FOR  THEIR  COMPLETE  DEVELOPMENT  ;  the 

asexual  development  (SCHIZOGONY)  takes  place  in.  the  blood  of 
man,  the  sexual  development  (SPOROGONY)  in  the  body  of  species 
of  the  genus  Anopheles.  The  transmission  to  man  is  effected  exclu- 
sively by  the  bite  of  Anophelinae,  which  harbour  in  their  salivary 
glands  the  mature  sporozoites  of  the  various  plasmodia  :  the  infec- 


THE    SPOROGONY  OF    THE    MALARIAL    PLASMODIA  101 

tion  of  Anopheles  is  effected  exclusively  by  the  mosquito  sucking 
the  blood  of  persons  suffering  from  malaria.  All  hypotheses  as 
to  any  other  mode  of  infection  do  not  hold  good. 

LITERATURE. 

(1)  MARSHALL,  R.  J.     The  Malaria  Parasite  (The  Lancet,  1896,  ii.,  p.  1187). 

(2)  MANSON,    P.     A  Method   of   Staining    the   Malaria   Flagellated    Organism    (Brit. 

Med.  Journ.,  1897,  ii.,  p.  68). 

(3)  MANNABERG,  J.     Die  Malariaparasiten.     Wien,  1893. 

(4)  SACHAROFF,  N.      Rech.  sur  les  hematoz.  des  oiseaux  (Ann.  Inst.  Pasteur,  1893, 

vii.,  p.  801). 

Ueber  die  selbstand.  Beweg.  d.  Chromos.  bei  Malariaparas.     (C.  f.  B.  u.  P., 
1895  [i],  xviii.,  p.  374). 

(5)  MACCALLUM,   W.  G.     On  the  Haematozoan  Infect,  of  Birds   (Journ.   Exp.  Med., 

Baltimore,  1898,  iii.,  p.  117;  and  C.  f.  B.,  P.  u.  I.,  1897  [i],  xxii.,  P-  44O). 

(6)  OPIE,  E.  L.       On  the  Hsemocytozoa  of  Birds  (Bull.  Johns  Hopk.  Hosp.,   1897, 

viii.,  No.  72,  p.  52). 

(7)  BIGNAMI  AND  BASTiANELLi.     Sulla  strutt.  d.  paras,  malar,  e  in  spec,  dei  gameti 

die  par.  estivoautumnali  (Atti  soc.  stud,  della  malaria,  1899,  i.). 

(8)  BIGNAMI   AND   BASTIANELLI.     Sulla  sviluppo  d.  paras,   d.   terzana  nell'  Anoph. 

claviger  (ibid.}. 
(())  KOCH,  R.     Ueb.  d.  Entwickelung    d.  Malariaparas.  (Z.  f.  Hyg.   u.    Inf.-Krankh- 

1899,  xxxii.,  p.  i). 
(10)  SCHAUDINN,   F.     Ueb.   d.   Generationswechsel   d.   Coccid.   u.   d.   neuere  Malaria, 

forsch.  (Sitzungsber.  Ges.  nat.  Frde.,  Berlin,  1899,  p.  159). 
(i  i)  RUGE,    R.      Unters.  iib.  d.  deutsche    Proteosoma    (C.  f.  B.,   P.    u.   L,    1901   [i], 

xxix.,  p.  187). 


PROPHYLAXIS. 

Although  our  experience  is  but  recent,  the  conclusions  arrived 
at  in  regard  to  the  prophylaxis  of  malaria  have  already  led  to 
brilliant  results.  Efforts  are  directed,  first  of  all,  to  induce,  if 
possible,  all  persons  harbouring  malaria  parasites  to  undergo  treat- 
ment, and  thus  bring  about  recovery,  in  order  to  simultaneously 
diminish  the  number  of  mosquitoes  that  contract  infection  from 
human  beings  and  thus  to  minimise  the  danger  of  transmission  to 
other  people.  Secondly,  the  measures  are  directed  against  the 
mosquitoes  themselves,  either  by  trying  to  destroy  their  breeding 
places  and  thus  kill  off  the  larvae  wholesale,  of  by  protecting 
persons  from  the  bite  of  mosquitoes.  The  protective  measures 
must  be  modified  in  accordance  with  the  local  conditions  and  other 
circumstances,  but  the  goal  is  most  rapidly  attained  in  malarial 
districts  by  preventing  the  bites  of  mosquitoes.  Mosquito  nets, 
which  have  been  so  long  in  use,  are  not  sufficient  for  this  purpose  ; 
more  effective  methods  must  be  found  to  prevent  mosquitoes 


102  THE   ANIMAL   PARASITES   OF   MAN 

from  invading  bed  and  sitting  rooms,  and  to  protect  those  occupied 
out  of  doors  in  the  twilight.  This  object  has  been  attained  with  the 
best  results.1  2 

H^EMATOZOA   IN    BERI-BERI. 

Under  the  term  beri-beri,  or  kakke,  is  understood  a  disease 
occurring  in  various  tropical  and  subtropical  countries  of  Asia, 
Africa,  America,  and  Australia.  It  occurs  endemically  and  epi- 
demically, and  by  predilection  affects  natives  and  immigrants  of 
the  coloured  races.  The  principal  symptoms  are  motor  disturb- 
ances and  disorders  of  sensation,  dropsy,  and  cardiac  disorders, 
which  are  attributable  to  a  degenerative  inflammation  of  numerous 
peripheral  nerves.  That  beri-beri  is  an  infectious  disease  we 
may  consider  proved  (Scheube).  Various  authors  have  found  the 
most  varied  bacilli  and  cocci  in  the  blood  of  beri-beri  patients 
who  not  rarely  arrive  at  European  ports.  Nevertheless,  none  of 
these  forms  can,  with  any  certainty,  be  recognised  as  the  agents 
of  the  disease.  Recently  several  authors  report  that  they  have 
found  amoeboid  forms  bearing  a  certain  resemblance  to  the 
malaria  plasmodia  in  the  blood  of  beri-beri  patients.  The  first 
statements  on  the  subject  were  those  of  Glogner,3  then  followed 
those  of  Fajardo.4  Although  the  latter  describes  several  forms 
which  point  to  a  multiplication  stage,  and  also  develop  black  or 
red  pigment,  their  protozoal  nature  does  not  seem  to  be  as  yet 
sufficiently  proved.  The  opinion  has  also  been  expressed  that  in 
such  cases  it  was  perhaps  a  question  of  a  combination  of  malaria 
with  beri-beri. 


1  On  this  subject  compare  :   Grassi,  B,,  "  Erst,  summar.  Ber.  ub.  Vers.  z.  Verhutung 
d.  Malaria  "  (C,.  f.  B.,  P.  u.  I.,  1900  [i],  xxviii.,  p.  535)  ;  Relaz.  dell'  esper.  di  preserv. 
d.  mal.  fatto  sui  fsrrovieri  n.  piana  di  Capaccio,  Milano,   1901  ;    Die  Malaria,   Jena, 
1901  ;  Blanchard,  R.,  "  Instr.  a  I'usage  des  med.,  d.  natur.  et  d.  voyag."  (Bull.  Ac.  med., 
Paris,  1900  [3],  xliv.,  p.  6  ;  Celli,  A.,  "  Die  neue  Prophyl.  d.  Mal.  in  Latium  "  (C.  f.  B., 
P.  u.  I.,  1900  [i],  xxviii.,  p.  696;    Die  Malaria  nach  d.  neuest.  Forsch.,  Wien,  1900; 
Nuttall,  G.  H.  F.,   "  Neuere  Forsch.  ub.  d.  Rolls  d.  Mosq.  bei  d.  Verbr.  d.  Malaria  "  (C.  /. 
B.,  P.  u.  I.,  1900  [i],  xxvii.,  pp.  193,  218,  260  and  328). 

2  Sambon  and    Low. — Reports  on    Two    Experiments    on    the   Mosquito-Malaria 
Theory. — (Transactions  of  the  Medico-Chirurgical  Society,  vol.  Ixxxiv.,  1902). 

3  Glogner,  M.,  "  Die  Stellung  d.  Beri-beri  unter  d.  Infectionskrankh."  (Arch.  f.  path. 
An.,  cxxxii.,  p.  50)  ;  "  Weitere  Beitr.  z.  Aetiol.  d.  multipl.  Neuritis  in  d.  Tropen  "  (ibid., 
1895,  cxli.,  p.  401);    "Neue  Unters.  ub.  d.  klin.   Verf.  u.  d.  Aet.,  der  Beri-berikrankh." 
(Arch.  f.  Schiffs-  und  Trop.-  Hyg.,  1897,  i-.  PP-  4-6,  125). 

4  Fajardo,  F.,  "  Von  d.  Hamotozoarie  d.  Beri-beri  u.  deren  Pigm."  (C.  f.  B.,  P.  u.  I., 
1898,  [i],  xxiv.,  p.   558);     "  Die  Hcemotozoarie  d.  Beri-beri  im  Gehirn"   (ibid.,   1900, 
xxvii.,  p.  249). 


IN    LEUCAEMIA  IO3 

IN    LEUCAEMIA. 

According  to  Lowit1  two  different  species  of  haemamceba  occur 
in  the  leucocytes  in  leucaemia — Hcemamceba  magna  in  myelaemia, 
and  H.  vivax,  later  termed  H.  parva,  and  still  later  H.  intranu- 
clearis,  in  lymphaemia ;  occasionally  mixed  infections  have  been 
observed.  The  disease  is  transmissible  to  rabbits,  in  which  as  a 
rule  it  takes  a  chronic  course ;  and  this  infection  can  be  trans- 
ferred from  animal  to  animal.  Although  the  author  describes 
stages  of  schizogony,  and  recently  has  also  reported  a  sexual 
propagation  of  the  parasites  in  the  same  host,  the  parasitical 
nature  of  the  bodies  observed  is,  to  say  the  least,  doubtful.  Turk2 
considers  them  to  be  artificial  products. 

THE  H^MOSPORIDIA  IN  BIRDS,  REPTILES,  AMPHIBIA  AND  FISHES. 

It  is  well  known  that  amongst  birds  a  large  number  of  species  belonging  to 
the  most  different  families,  and  inhabiting  various  parts  of  the  earth,  harbour 
hsemosporidia.  Hitherto  the  life-history  of  Plasmodium  prcecox,  Gr.  and 
Fel.  (=  Hcsmoproteus  'Danilewskyi,  Kruse  ;  =  Proteosoma  Grassii,  Labbe),  lias 
been  the  best  investigated.  The  presence  of  this  parasite  in  the  blood 
of  birds  causes  an  elevation  of  temperature  of  i°-i'5°.  It  is  worthy  of 
note  that  schizogony,  which  occupies  four  or  five  days,  is  accomplished 
in  two  ways  :  in  the  one  there  are  only  six  to  seven  merozoies  arranged 
in  a  rosette  shape,  in  the  next  the  schizonts  are  considerably  larger  and 
divide  into  very  numerous  merozoies.  Ross  was  the  first  to  establish  the 
fact  that  mosquitoes  of  the  genus  Culex  are  the  hosts  of  this  parasite 
— in  Europe,  Culex  pipiens,  L.,  and  C.  nemorosus,  Meig.,  and  in  India 
C.  fatigans,  Wied.  Within  the  body  of  the  mosquito  copulation  and  sporo- 
gony  are  accomplished  in  a  manner  similar  to  that  of  the  malaria  plas- 
modia  of  man  within  Anopheles.  By  means  of  the  bite  of  the  mosquito 
the  sporozoies  collected  in  the  tubules  of  the  salivary  glands  pass  into 
the  blood  of  the  bird.  The  infection  is  particularly  dangerous  to  nestlings, 
and  also  to  older  birds  during  moulting. 

Halteridium  Danilewskyi  (Gr.  et  Fel.)  is  a  second  species  likewise  found 
in  numerous  kinds  of  birds,  but  which  does  not  affect  the  host  to  the 
extent  of  the  first-named  species.  The  mature  schizonts  are  of  a  dumb- 
bell shape,  and  the  merozoies,  for  the  development  of  which  about  a 
week  is  necessary,  are  grouped  like  rosettes  or  morulae  at  the  two  thickened 
extremities.  The  microgametocytes  are  also  dumb-bell-shaped.  The  further 
development  is  still  little  known,  but  mosquitoes  of  the  genus  Culex  are 
likewise  the  hosts  of  this  parasite. 

1  Lowit,  M.,  "  Die  AetioL  d.  Leukaemie  "  (C.  f.  B.,  P.  u.  I.,  1899  [i],  xxv.,  p.  503)  ; 
"  Weitere  Unters.   ub.  d.  Paras,  d.  Leuk."  (ibid.,  1900,  xxvii.,   p.    503)  ;    Die  Leukaemie 
als  Protozoen-Infection,  Wiesbaden,  1900. 

2  Turk,  "  Ueb.   d.  Htemamceben  Lowit' s   im  Blute   Leukaemischer  "    (Med.    Woche., 
1900,  No.  18,  p.  173). 


IO4 


THE   ANIMAL   PARASITES   OF   MAN 


Still  a  third  species  known  as  Lankesterella  avium  (Labbe)  has  been 
observed,  particularly  in  the  blood  of  birds  of  prey.  Only  the  stages  of 
schizogony  are  known. 

The  number  of  haemosporidia  known  in  the  blood  of  reptiles  is  far 
more  numerous,  and  all,  with  one  exception,  are  referred  to  the  genus 
Hcemogregarina ;  *  they  are,  as  a  rule,  comparatively  elongated  creatures 


FIG.  45.  — Hcemogregarina  Stepanowi, 
Danil.,  in  the  red  blood  corpuscles  of 
Cistudo  europaa.  (After  D anile wsky. ) 


FIG.  46. — H&mogregarina  Ste- 
panowi, Danil.,  in  schizogony. 
The  blood  corpuscle  is  still  there, 
its  nucleus  at  the  edge ;  to 
the  right  two  merozoites.  (After 
D  anile  wsky.) 


(fig.  45)  that  occasionally  attain  a  length  double  that  of  the  blood  cor- 
puscles, and  also  occur  free  in  the  blood  plasma.  As  we  do  not  know 
the  entire  development,  and  only  schizogony  (fig.  46)  has  been  observed, 
T  will  confine  myself  to  the  enumeration  of  the  species  : — 


i.     Hcemogregarina  Stepanowi,  Danil.  . . 


2. 

3- 
4- 

5- 

6. 
7- 


8. 

9- 
10. 


Labbei,  Born. 
Laverani,  Simond  . . 
Mesnili,  Simond     .  . 
Billeti,  Simond       .  • 

Hankini,  Simond   . . 
crocodilinorumJSdrn . 


lacertarum,  Danil.  . . 

Lacazei,  Labbe   ,  • . , 
platydactyli,  Billet . . 


Cistudo  europ&a,  Trionyx  sp., 

Testudo  marginata. 
Platemys  sp.,  Clemmys  elegans, 
Cryptopus  granosus, 
Emys  tectum, 
Trionyx  stellatus, 

Gavialis  gangeticus, 
Crocodilus  frontatus,  Alligator 
mississipiensis , 

Lacerta  muralis,  L.  agilis,  L. 

vividis,  L.  ocellata, 
Lacerta  agilis,  L.  muralis, 
Platy.  mauritanicus , 


11.  ,,  bungari,  Billet     "".,  Bungarus  fasciatus, 

12.  ,,  pythonis,  Billet       ..  Python  reticulatus, 

13.  ,,  sp.  Billet     ..          ..  Tropidonotus  stolatus, 

14.  ,,  Joannoni,  Hagenm.  Macroprotodoa  cucullatus, 

15.  ,,  colubri,  Born.          ..  Coluber  cssculapii. 

This  list  is  not,  however,  complete,  because  several  authors  have  not  given 
names  to  the  haemosporidia  they  have  found  in  reptiles.  The  total  number 
harbouring  haemosporidia  with  which  we  are  so  far  acquainted  comprises  thirty 


1  It  is  doubtful  if  this  species  also  occurs  in  invertebrate  animals,  though  a  H.  nasuta 
Eisen,  from  an  Oligochaete,  has  been  mentioned  in  literature. 


H^MOSPORIDIA    IN    BIRDS,    REPTILES,    ETC.  105 

species  appertaining  to  the  Ophidia,  seven  to  the  Saurians,  three  to  the  Croco- 
diles, and  nine  to  the  Chelonians.  One  of  these  species  (from  a  tortoise; 
Trionyx  indicus}  is  classified  as  belonging  to  the  genus  H&mamceba 
(—  plasmodium),  and  has  been  described  by  Simond  as  H.  Metschnikowi. 

The  Haemosporidia  of  the  amphibians  are  usually  ascribed  to  the  genus 
Lankesterella  (—  Drepanidium,  Lank.,  nee  Ehrb.).  The  differentiation  of  the 
species  has  been  disputed  :  the  species  we  have  known  longest,  as  well  as 
best  (see  above,  p.  83)  is  Lank,  minima  (Chauss),  (—  Drepanidium  ranarum, 
R.  Lank.),  from  Rana  esculenta.  Drepanidium  princeps,  Labbe,  is  identical 
with  this  species,  and  very  probably  also  Laverania  ranarum,  Gr.  et  Fel.  (= 
Hcemogregarina  ranarum,  Kruse),  and  Dactylosoma  splendens,  Labbe.  Lank, 
monilis  (Labbe)  may  be  a  particular  species  that  certainly  resembles  Lank, 
minima  in  the  early  stages,  but  differs  from  it  when  fully  developed.  Perhaps 
Drepanidium  magnum,  Grassi  and  Fel.,  is  also  an  independent  species,  as  is 
certainly  H&mogregarina  Riedyi,  Eisen.  In  this  Calif ornian  variety  Batra- 
choseps  attenuatus  is  the  host  ;  all  other  forms  are  European  and  live  in 
Rana  esculenta.  One  other  form,  known  formerly  as  Cytamceba  bacterifera, 
Labbe,  from  the  green  frog,  is  to  be  entirely  eliminated,  because  what 
was  so  termed  is  not  a  living  organism  at  all  but  phases  of  degeneration 
in  the  blood  corpuscles  induced  by  long  bacteria  (Laveran).1 

Gros  (1845)  and  Wedl  (1850)  appear  to  have  been  the  first  to  see  Haemo- 
sporidia in  the  blood  of  fishes.  Danilewsky  (1889)  gives  a  short  account  of  the 
latter  in  Perca  fluviatilis,  and  two  species  have  been  recently  described  by 
Laveran  and  Mesnil2  (Hcemogregarina  Simondi,  from  Solea  vulgaris,  and  H. 
bigemina  from  Blennius  pholis  and  B.  gassorugine). 


THE  MOST  IMPORTANT  LITERATURE. 

DANILEWSKY,  B.     Die    Haematoz.    d.   Kaltbliier  (Arch.  f.  mirk.  An.,  1885,  xxiv.,  p. 

588). 

Mater,  p.  serv.  a  la  paras,  du  sang  (Arch.  slav.  de  biol.,  1886,  i.,  pt.  89). 
III.  Hemat.  des  lezards  (ibid.,  p.  364).     IV.  Hem.  d.  tortues  (ibid.,  1887,  ii.,  pp. 

33,  157.  370). 

La  parasitol.  comp.  du  sang.     Charkow,  1889  (Russ.). 
Develop,  d.   paras,  malar,  dans  les  leucocytes  des  oiseaux  (Ann.    Inst.   Pasteur, 

1890,  p.  427). 
Sur  les  microb.  d'infect.  mal.  (ibid.,  p.  753).     Contrib.  a  1'etude  de  la  microbiose 

malar,  (ibid.,  1891,  p.  758). 
GRASSI,  B.,  and  R.  FELETTI.     Malariapar.  i.  d.  Vog.  (C.  f.  B.  u.  P.,  1891,  ix.,  pp.  403, 

429,  461). 

Weiteres  z.  Malariafrage  (ibid.,  1891,  x.,  pp.  449,  481,  517). 
Contrib.   allo  stud.  d.  paras,  mal.  (Atti  Ace.  gioenea  sc.  nat.,  Catania  v.,  Ser.  4, 

1892). 
CELLI,  A.,  and  F.  SANFELICE.     Sui  paras,  d.  glob,  rosso  nel  uomo  e  negli  anim.  (Ann. 

1st.  d'ig.  esp.  R.  Univ.  Roma.  N.S  ,   1891,  i. 
Fortsch.  d.  Med.,  1891.     Nos.  11-15. 
KRUSE,  W.     Ueb.  Blutparas.  (Virch.  Arch.  path.  An.,   1890,  cxx.,  p.  451,  and  cxxi., 

P-  359)- 


1  Laveran,  A.,    "  Sur  le  bacille  parasite  des  hematics  de  rana  esculenta  "  (C.  R.  soc* 
biol.,  Paris,   1899,  i.,  p.  355. 

2  Laveran,  A.,  and  Mesnil,  F.,  "  Deux  he.mogr.  nouv.  d.  paras."  (C.  R.  Ac.  sc.,  Paris, 
1901,  cxxxiii.,  p.  572.) 


106  THE   ANIMAL   PARASITES   OF   MAN 

LABBE,  A.     Rech.  zool.  et.  biol.  sur  les  par.  endoglob.  du  sang  d.  vertebr.  (Arch.  zool. 
exp.  et  gen.,  1894  [3],  ii.,  p.  55). 

Sporozoain:   Das  Thierreich.     Books.      1899. 

OPIE,  E.  L.     Haemacytozoa  of  Birds  (Bull.  Johns  Hopk.  Hosp.,  1897,  vm->  No-  72)- 
Ross,  R.     Cultiv.  of  Proteosoma  in  Grey  Mosq.     Calcutta,  1898. 
HAGENMULLER,  P.  .  Hernosp.  d'un   ophid.  du    syst.  europ.   (Arch.  zool.  exp.  et  gen. 

1898  [3],  vi.,  Note  No.  4,  p.  li). 
BILLET,  A.     Laverania  bungari  (C.  R.  soc.  biol.,  1895,  xlvii.,  p.  30). 

Hemat.  endogl.  d.  Platydact.  (ib.,  1900,  No.  21,  p.  547). 

Hem.  endogl.  des  Trionyx  (ib.,  1901,  No.  10,  p.  257). 
LAVERAN,  A.     Hemat.  endoglob.  chez  Padda  oryzivora  (C.  R.  soc.  biol.,  1898,  v.,  p. 


Hemogreg.  stepanowi  (ib.,  pp.  885,  919). 
Drepanid.  ranar.  (ib.,  p.  977). 
Laverania  danilewskyi  (ib.,  1899,  [n]  i.,  p.  603). 
LANGMANN,  G.      On  haemosp.  in  Americ.  Rept.  and  Batrach  (New  York  Med.  Journ., 

1899). 
SIMOND,  P.  L.     Contrib.  a  1'etude  d.  hemat.  endogl.  d.  reptiles  (Ann.  Inst.  Pasteur, 

1901,  p.  319). 

LUTZ,  A.     Drepanidien  d.  Schlangen  (C.  f.  B.,  P.  u.  L,  1901,  xxix.,  p.  390). 
BORNER,  C.     Unters.  lib.  Haemospor.  I.  (Z.  f.  wiss.  Zool.,  1901,  Ixix.,  p.  398). 
RUGE,  R.     Unters.  iib.  d.  deutsche  Proteosoma  (C.  f.  B.,  P.  u.  L,  1901  [i],  xxix.,  p.  187). 
GALLI-VALERIO,  B.     Unters.  iib.  d.  Haemosp.  d.  Alpenvogel  (C.  f.  B.,  P.  u.  L,  1902, 

[i],  xxxi.,  Orig.,  p.  162). 

SAMBON,  L.  W.,  and  Low,  G.  C.  —  Report  on  Two  Experiments  on  the  Mosquito- 
Malaria  Theory  .  Appendix  A.  Haemocytozoa  of  Animals  (Medico  Chirur- 
gical  Transactions,  London,  1902). 

Order  4.     Myxosporidia,  Biitschli. 

These  parasites,  which  were  discovered  by  Joh.  Miiller  (i),  live  principally 
in  fishes,  and  occasionally  cause  destructive  epidemics  amongst  their  hosts. 
Miiller  first  observed  them  in  the  form  of  whitish-yellow  pustules  on  the 
skin  or  on  the  gills  of  various  fishes  ;  these  pustules  contained  masses  of 
small  shell-covered  bodies  with  or  without  tails  (Psorospermia,  see  fig.  47). 
Similar  bodies  were  also  found  in  the  air  bladder  of  the  Torsk  (2). 
Creplin  (3)  simultaneously  demonstrated  the  resemblance  of  the  cysts 
harbouring  the  Psorospermia  (Psorosperm  tubes)  to  the  "  pseudonavicell- 
cysts  "of  a  gregarine,  as  described  by  v.  Siebold,  and  Dujardin  (4) 
considers  that  there  is  possibly  some  connection  between  the  sarcode-like 
psorosperm  tubes  and  the  spores  they  contain  (psorosperms),  with  the 
developmental  stages  of  monocystide  gregarines  from  the  vesicula  seminalis 
of  earth-worms.  The  relationship  of  the  psorosperm  tubes  was  placed  on 
a  firmer  basis  by  Ley  dig  (5)  and  Lieberkiihn  (6).  The  former  found 
numerous  forms  in  salt  water  fish  and,  in  species  which  live  free  in  the 
gall  bladder  of  cartilaginous  fishes,  he  discovered  that  the  psorospermia 
originate  in  a  manner  similar  to  the  gregarines  ;  while  Lieberkiihn  studied 
the  myxosporidia  in  the  bladder  of  the  pike  (fig.  49),  and  observed  their 
amoeboid  movements,  as  well  as  the  formation  of  the  psorospermia,  from 
each  of  which  a  small  amoeboid  body  escaped  (fig.  53),  a  discovery  that 
was  confirmed  by  Balbiani  (7).  The  same  author  also  found  that  spiral 
filaments  were  enclosed  in  the  so-called  polar  body  of  the  psorosperms, 
and  that  these  could  be  protruded  (fig.  56,  d,  and  fig.  59). 

The  term  which  at  the  present  day  is  universally  applied  to  the 
psorosperm  tubes  (myxosporidia)  was  introduced  by  Biitschli  (8),  who  studied 
not  only  the  structure  and  development  of  the  spores,  but  also  the 
protoplasmatic  body  of  the  parasites  in  question,  and  confirmed  the 


MYXOSPORIDIA 


I07 


occurrence  of  numerous  nuclei.  Recently  the  following  authors  have 
contributed  important  additions  to  our  knowledge  of  th?  myxosporidia  : 
—Perugia  (9),  Thelohan  (10),  Mingazzini  (n),  L.  Pfeiffer  (12),  L.  Cohn 
(13),  and  Donein(i4);  while  the  presence  of  this  parasite  outside  ^the 
class  of  fishes  has  become  known  through  Lutz,  Laveran,  and",  others. 


a.  b.  c.  d. 

FIG.  47.  —  Part  of  a  gill  of 
Leuciscus  vutilus,  (natural  size), 
with  two  myxosporidia  (a,  b,  d) 
Spores  of  myxosporidia  from 
Esox  lucius  (c)  Spores  from 
Platystoma  fasciatum  (after  J. 
Miiller). 


a  b 

FIG.  48.  —  (a)  Myxobolus 
Mulleri,  Biitschli,  on  the  lobe 
of  the  gill  of  a  cyprinoid  ;  (b) 
the  tailless  spore,  with  the 
polar  bodies  and  their  nuclei 
and  the  sporozoite  (after 
Biitschli). 


The  species  causing  diseases  in  fishes  have  been  described  by  Ludwig 
(15),  Railliet  (16),  Weltner  (17),  L.  Pfeiffer  (12),  Zschokke  (18),  Hofer  (19), 
Doflein  (14),  Gurley  (20),  and  in  regard  to  classification  the  works  of 
Thelohan  (21)  and  Gurley  (22)  may  be  mentioned.  The  myxosporidia  live 
either  free  on  the  epithelial  surfaces  of  hollow  organs  (gall  or  urinary  bladder, 


FIG.  49. — (a)  Myxidium  Lieberkuhnii  B., 
from  the  urinary  bladder  of  Esox  lucius  ;  (&)a 
pansporoblast  ;  (c)  complete  spore  (after 
Biitschli). 


b. 


renal  tubules,  but  never  in  the  intestine),  or  are  enclosed  in  the  tissues  of 
their  host.  The  gills  and  muscular  system  are  their  favourite  habitat  •  but 
other  tissues  or  organs,  with  the  exception  of  the  bones  and  cartilages,  are 
apt  to  be  attacked. 

The   free   forms   move   with    the   assistance   of   variously    shaped   pseudo- 
podes,    have   a   constant    form,    or   may    exhibit   contractions   of    the   body  ; 


io8 


THE    ANIMAL    PARASITES    OF    MAN 


the  tissue-parasites  often  attain  a  considerable  size,  so  that  the  integument 
of  the  host  forms  protuberances  over  them  ;  they  are  of  a  roundish  or 
irregular  shape,  which  does  not  change,  except  as  regards  the  alterations 
induced  by  growth  ;  they  are  usually  enveloped  in  a  connective  tissue  covering 
formed  by  the  host. 

The  protoplasmatic  body  usually  permits  the  finely  granular  ectosarc 
to  be  distinguished  from  the  coarsely  granular  endosarc  ;  occasionally  the 
former  is  thickened  into  a  kind  of  integument.  In  addition  to  various  enclo- 
sures, there  are  as  a  rule  numerous  nuclei,  which  divide  mitotically,  and 
all  originate  from  the  primary  nucleus  of  the  early  stage  (amoeboid  germ), 
enclosed  in  the  spore. 


FIG.  50. — Schema  of  a  spore  of  Myxo 
bolus  :  (a)  One  polar  capsule  has  protruded 
the  filament  ;  two  nuclei  and  a  "  vacuole  " 
in  the  sporozoite  ;  (b)  spore  seen  in  optical 
section — the  two  polar  capsules  in  the 
interior  (after  Doflein). 


The  development  of  the  spores  commences  long  before  the  ultimate  size 
is  attained,  and  in  some  species  their  number  is  remarkably  large,  in 
others  small,  or  limited  to  two  only  (Polysporea — Disporea).  The  spores 
(fig.  50)  are  surrounded  by  two  concave  shells,  turned  facing  each  other 
and  united  at  the  borders  ;  the  external  surface  may  be  smooth  or 
sculptured,  and  may  carry  one.  or  two  .caudal  appendages  at  the  one 
pole  ;  they  enclose  at  the  pointed  anterior  pole  two  formations  resembling 
nettle-capsules,  the  polar  capsules,  the  spirally  rolled  hollow  filaments  of 
which  may  be  protruded  spontaneously  or  through  the  action  of  certain  agents. 
The  posterior  larger  half  of  the  internal  space  is  occupied  by  a  proto- 


FIG.  51. — Myxidium  lieberkuhnii  : 
(a)  Pansporoblast,  with  four  nuclei  ; 
(b,  c]  pansporoblast  with  eight  nuclei ; 
(d)  pansporoblast  divided  into  two 
sporoblasts,  after  expulsion  of  two 
nuclei ;  (e)  pansporoblast  with  10 
nuclei  (after  L.  Cohn). 


plasmatic  body  (amoeboid  germ,  sporozoite),  containing  one  or  two  nuclei 
and  a  so-called  vacuole,  which  represents  the  young  myxosporidia  ;  it 
becomes  free  in  consequence  of  the  bursting  open  of  the  two  halves  of  the 
shell,  and  then  can  execute  amoeboid  movements  (fig.  53). 

The  spores  are  formed  by  a  portion  of  protoplasm  (pansporoblast) 
gathering  round  each  nucleus  of  the  parent  (sporont),  the  nucleus  again 
repeatedly  dividing  until  eight  to  ten  daughter  nuclei — rarely  more — are  formed 
(fig.  51)  ;  the  protoplasm  of  the  pansporoblast  then  divides  into  two  halves 
(sporoblasts),  in  which  the  nuclei  are  equally  distributed  after  two  -of 
them  have  been  extruded.  Accordingly,  each  sporoblast  contains  at  least 


MYXOSPORIDIA  IOQ 

three  nuclei.  The  protoplasm  subsequently  gathers  round  each  nucleus. 
Of  the  three  cells  thus  formed,  which  develop  a  shell  on  the  exterior 
surface,  two  pass  into  the  polar  body  and  one  into  the  amoeboid  germ, 
the  nucleus  of  which,  sooner  or  later,  again  divides  (fig.  52). 

In  pansporoblasts  with  ten  nuclei,  four  nuclei  are  left  for  each  sporoblast 
after  the  extrusion  of  two  ;  the  protoplasm  gathers  round  them  in  such  a  way 
that  it  forms  two  mononuclear  cells,  the  future  polar  bodies,  and  one  binu- 
cleated  cell,  the  amoeboid  germ.  In  those  few  cases  in  which  twelve  to  fourteen 
nuclei  appear  in  the  pansporoblasts  four  pole-capsules  appear  in  each  spore. 

FIG.  52. — (a,  b)  Myxoproteus 
ambiguus  ;  (a)  sporoblast  showing 
position  of  the  two  polar  capsules 
and  the  sporozoit  ;  (b)  pansporo- 
blast  with  two  older  sporoblasts, 
the  rejected  nuclei  being  between 
them ;  the  nucleus  in  the  sporo- 
zoits  already  divided  ;  (c)  mature 
spore  of  Myxobolus  cyprini  (after 
Doflein). 

The  spores,  no  doubt,  fulfil  the  mission  of  effecting  transmission  to 
other  hosts  ;  infection  occurs  by  the  ingestion  of  the  parasites  per  os  after 
their  escape  by  some  means  from  their  host.  Thelohan  (10)  has  demon- 
strated that  the  shells  of  the  spores  soon  open  under  the  influence  of 
the  intestinal  juices,  thus  allowing  the  young  myxosporidia  to  escape. 
Their  further  history  is  unknown  ;  but  it  may  be  surmised  that  they  either 
travel  direct  to  the  organs  usually  affected  (gall  bladder,  urinary  bladder), 
or  are  distributed  in  the  body  by  means  of  the  circulation. 

In  a  few  species  increase  has  been  observed  to  take  place  by  means  of 
division  or  budding,  which  leads  to  a  more  aggravated  infection .  of  the 
already  affected  host  ;  possibly  this  process  (multiplicative  propagation  by 
plasmotomy)  is  very  much  more  frequent  than  we  are  aware  of. 

FIG.  53. — Spores  of  a  myxosporidium  from  the  gills 
of  Gobio  ftuviatilis,  the  contents  of  which  are  escaping. 
600/1.  (after  Biitschli). 

Whether  there  is  copulation,  and  at  which  stage  it  takes  place,  is  as 
yet  unknown. 

Myxosporidia  are  divided  into  two  sections — Disporea  and  Polysporea — 
according  to  whether  they  form  only  two  or  several  spores  during  their 
growth  ;  the  former,  up  to  the  present,  appear  to  consist  of  two  genera 
limited  to  fishes,  which  are  easily  distinguishable  by  the  shape  of  the  spores  : 
Leptotheca,  Thel.,  with  a  rounded  spore-shell,  and  Ceratomyxa,  Thel.,  with  a 
very  elongated  spore-cell.  The  larger  number  of  genera  appertain  to  the 
Polysporea,  which  are  divided  into  three  families  : 

(1)  Amoeboid-germ  with  a  vacuole  ( (a)  With  two  pole-capsules — Myxidiidce, 

the  contents  of  which  do  notj 

stain  with  iodine.  [(b)  With  four  pole-capsules. — Chloromyxidce. 

(2)  Amceboid-germ  with   a  vacuole  stainable  with  iodine.      Spores  with   two 

pole-capsules — Myxobolidcs. 
For  further  subdivisions  the  differences  of  the  spores  are  principally  utilised 


IIO  THE   ANIMAL   PARASITES    OF    MAN 

LITERATURE. 

(1)  MULLER,  J.     Ueb.  eine  eigenth.  krankh.  paras.  Bildung  mit  specif,  organis.  Samen 

korp.  (Arch.  f.  An.  u.  Phys.,  1841,  p.  477). 

(2)  MULLER,  J.,  and  A.  RETZIUS.     Ueb.  paras.  Bildungen  (ib.,  1842,  p.  193). 

(3)  CREPLIN,   J.  C.  H.      Beschr.  d.  Psorosp.  des  Kaulbarsches    nebst    Benierk.  iib 

die  der  Plotze  (Arch,  f  Naturg.,  1842,  viii.,  i,  p.  61). 

(4)  DUJARDIN,  F.     Hist  nat.  d.  helm.    Paris,  1845,  P-  643. 

(5)  LEYDIG,  F.     Ueb.  Psorosp.    u.   Gregarinen    (Arch.  f.  An.  u.  Phys.,  1851,  p.  221). 

(6)  LIEBERKUHN,  N.     Ueb.  d.  Psorosp.  (ib.,  1854,  p.  349). 

(7)  BALBIANI,  G.     Sur  1'organis.  et   la  nature  d.  psorospermies  (C.  R.  Ac.  sc.,  Paris, 

1863,  Ivii.,  p.  157). 

(8)  BUTSCHLI,  O.     Z.    Kenntn.    d.   Fischpsorosp.  (Z.   f.   w.    Z.,    1881,  xxxv.,  p.  629); 

Protozoa  in  :    Bronn's  Cl.  u.  Ordn.  d.  Thierr.,  I.  Lpzg.,  1882,  i.,  p.  590). 

(9)  PERUGIA,   A.     Sulle    myxosporidie    d.    pesci    marini    (Bull,    scientif.    Ann.,  1889, 

xii.,  1890,  xiii.  p.  10).  * 
(10)  THELOHAN,  P.   In  numerous  reports  published  in  C.  R.  soc.  biol.,  Paris,  and  C.  R. 

Ac.  sc.  Paris,  1889-1894,  as  well  as  in  Rech.  sur  les  Myxosp.  (Bull,  scient. 

France  et  Belg.,  1895,  xlvi.,  p.  100). 

(n)  PFEIFFER,   L.     Die   Protoz.    als   Krankheitserr.    2   edit.     Jena,    1891. 
Unters.  iib.  d.  Krebs.     Jena,  1892. 

(12)  MINGAZZINI. 

(13)  COHN,  L.     Ueb.  d.  Myxospor.  v.  Esox  lucius  u.  Perca  fluviat.     In.-Diss.   Kgsbg.. 

1895,  and  Zool.  Jahrb.  Abth   f.  Anat.,  ix.,  1895. 

(14)  DOFLEIN,  F.     Stud.  z.  Nat.  d.  Protoz.    III.   Ueb.   Myxosp.    (Zool.    Jahrb.   Anat., 

xi.,  1898,  p.  281). 

(15)  LUDWIG,    H.      Ueb.    d.    Myxosp.   d.   Barben  i.  d.  Mosel    (Jahr.-Ber.    d.   Rhein. 

Fisch.-Vereins,  1888-89,  P-  27)- 

(16)  RAILLIET,  A.     La   mal.  d.  barbeaux  de  la  Marne  (Bull.    soc.    centr.    d'aquicult. 

France  pour  1890,  ii.,  p.  117). 

(17)  WELTNER,  W.      Ueb.    Myxosp.  i.   d.   Eiern  v.   Esox    lucius    (Stzgsb.    Ges.    nat. 

Frde.  Berlin,  1892,  p.  28). 

(18)  ZSCHOKKE,  F.     Myxosp.  d.  Gttg.  Coregonus  (C.  f.  B.,  P.  u.  L,  1898  [i],  xxiii.,  pp. 

602,  646,  699  ;    and  Mitth.  d.  nat.  Ges.  Luzern,  1898,  2,  p.  205). 

(19)  HOFER,  B.     Die  sogen.  Pockenkrankh.  d.  Karpfen  (Allg.  Fisch.-Ztg.,   1896,  pp.  2, 

28,  1 86  ;   and  ib.,  1902,  p.  22). 

(20)  GU.RLEY,  R.     The  Myxosp.  or  psorosp.  of  Fish,  and  the  Epid.  Produc.  by  them 

(Rep.  U.S.  Comm.  of  Fish  and  Fisher,  f.  1892,  Washington,  1894,  p.  65). 

(21)  THKLOHAN,  P.     Observ.  sur  les  myx.  et  essai  de  classif.  des  ces  org.  (Bull,  soc, 

•phil.,  Paris,  1892  [8],  iv.,  p.  165). 

(22)  GURLEY,   R.     On  the  Classific.    of   the  Myxosp.   (Bull.  U.S.   Fish  Com.   f.    1891. 

Washington,  1893,  p.  407). 


Order  5.     Microsporidia,  Balbiani. 

These  are  the  forms  discovered  in  the  stickleback  by  Gluge  in 
and  in  Coccus  hesperidum  by  Leydig  in  1853,  and  which  have  later  been 
found  in  numerous  other  arthropoda,  insects  and  arachnoids.  They  acquired 
particular  importance  when  it  was  discovered  that  they  were  the  cause  of 
the  .pebrine  sickness  (gattina  of  the  Italians)  which  caused  so  much 
destruction  amongst  silkworms  (Bombyx  mori}.  Pasteur  (1870)  and  especially 
Balbiani  participated  in  the  researches  on  Nosema  bombycis,  and  it  was  the 
latter  who  classed  the  "  pebrine  bodies  "  or  "  psorospermia  of  the  arthropoda  }> 
amongst  the  sporozoa  as  microsporidia  (1884).  But  the  occurrence  of  this, 
group  is  not  confined  to  insects  and  arachnoids,  they  are  now  known  to 
occur  also  in  crustaceans,  worms,  bryozoa,  fishes,  amphibians  (Rana}  and 
reptiles  (Emys} ;  they  have  even  been  known  to  form  tumours  in  fishes, 
similar  to  those  formed  by  many  myxosporidia. 

These  small  protoplasmatic  creatures  seem   to  parasitise  in  all  cells  and 


MICROSPORIDIA 


III 


to  spare  no  tissues  ;  they  form  pansporoblasts,  with  or  without  envelopes, 
in  the  interior  of  their  body,  which  then  grows  still  further,  or  the  latter 
is  completely  occupied  by  the  pansporoblasts  ;  generally  each  pansporoblast 
develops  a  great  number  of  spores,  rarely  as  few  as  four  or  eight.  The  spores 
are  remarkably  small,  are  usually  oval  or  pear-shaped,  and  surrounded  by  a 
comparatively  thick  shell  which  probably  always  consists  of  two  halves. 
At  one  pole,  the  anterior  one,  there  is  always  one  pole-capsule  with  a 


FIG.  54, — a,  Section  through 
the  abdominal  wall  of  a  silk- 
worm, whose  epithelial  cells 
contain  Microsporidia  (Nosema 
bombycis)  ;  b,  a  spore  the  con- 
tents of  which  are  escaping ; 
c — e,  sporulation  stages.  (After 
Balbiani.) 


c.  d. 

projectile  filament,  only  observable  by  means  of  reagents.  For  this  reason 
some  authors,  since  this  fact  has  become  known,  have  included  the  micro- 
sporidia  as  Glugeida  or  as  cryptocyst  myxosporidia  of  the  Blatter.  The 
spores,  moreover,  contain  the  "  amosboid-germ,"  the  exit  of  which  from 
the  spore  Balbiani  had  already  seen. 

£J/The  manner  of  infection  as  regards  the  silkworms  is  well  known  ;  it 
occurs  through  the  ingestion  of  the  spores  which  reach  the  food  already 
contaminated  by  the  excrements  of  infected  silkworms  ;  probably  an 


FIG.  55. — Nosema  bombycis,  Naeg.  Spores  treated  with 
nitric  acid,  thus  rendering  the  polar  capsule  perceptible,  and 
the  filament  has  protruded  itself  from  the  one  spore.  (After 
Thelohan.) 


increase  of  the  parasites  within  the  infected  host  takes  place  in  some  way 
as  yet  unknown  to  us.  This  leads  to  the  enormous  infection  of  all  the 
tissues  and  organs  that  is  so  frequently  observed,  and  to  which  the  silk- 
worms succumb  ;  or,  on  the  other  hand,  the  chrysalis  stage  and  the 
formation  of  cocoons  is  omitted  because  the  salivary  glands  are  also 
attacked.  When  the  infection  is  less  extensive  the  silkworms  not  only 
become  pupae,  but  the  moths  emerge,  'and  often  deposit  infected  eggs,  so 
that  the  disease  may  also  be  congenital.  Fortunately,  however,  eggs  may 
be  recognised  as  infected  under  the  microscope,  as  Pasteur  has  shown, 
and  as  the  little  caterpillars  may  transmit  the  disease  to  healthy  ones 
they  are  therefore  promptly  destroyed. 


112  THE   ANIMAL    PARASITES    OF    MAN 

The  species  of  Thelohania  that  occur  in  the  muscular  system  of  river 
craw-fish  and  Palaemonidae  are  likewise  capable  of  causing  diseases,  which, 
however,  have  nothing  to  do  with  typical  craw-fish  plague,  as  the  latter 
is  decidedly  and  solely  caused  by  the  Bacillus  pestis  astaci,  Hofer. 

Four  genera  are  now  distinguished  in  the  Microsporidia  :  Thelohania, 
Henneg.,  Nosema  n&gali  (—  Glugea,  Thel.),  Plistophora,  Gurley,  and  Gurleya 
Dofl.1 


Order  6.     Sarcosporidia,  Balbiani. 

This  group,  which  is  the  one  that  has  been  least  studied,  was  first 
discovered  by  Miescher  (i)  in  1843.  This  author  found  milk-white  fila- 
ments running  parallel  with  the  direction  of  the  fibres  in  the  voluntary 
muscles  of  domestic  mice  ;  they  were  visible  to  the  naked  eye,  and  proved 
to  be  cylindrical  tubes  rounded  off  and  tapering  at  each  end  ;  they  were 
as  long  as  the  muscular  fibres,  were  enveloped  in  a  membrane,  and  con- 
tained innumerable  elongated  or  kidney-shaped  bodies  and  a  smaller 
number  of  little  globular  forms.  J.  Hessling  (2)  confirmed  the  occurrence 
of  these  "  Miescher's  tubes  "  within  the  muscular  fibres,  this  author  having 
discovered  the  same  formation  in  the  miocardium  of  deer,  cattle  and 
sheep.  Both  investigators  considered  them  to  be  pathological  transforma- 
tions of  the  muscles,  v.  Siebold  (3),  from  his  own  experiences,  regarded 
them  as  fungus-like  entophytes. 

Rainey  (4)  discovered  similar  formations  in  the  muscular  system  of  domestic 
pigs,  and  proclaimed  them  to  be  early  stages  of  the  Cysticercus  cellulose, 
which  error  Leuckart  (5)  rectified,  simultaneously  emphasising  their  rela- 
tionship with  Myxosporidia.  Both  these  authors  found  them  in  the  mus- 
cular fibres  and  both  observed  that  they  possessed  a  thick  striated  mem- 
brane. Manz  (6)  published  the  results  of  more  minute  investigations 
on  the  structure  and  contents  of  the  cylinders.  This  observer  also 
recognised  the  disease  in  rabbits  and  attempted  to  cultivate  the  parasites  ; 
he  also  tried  to  induce  experimental  infection  in  guinea-pigs,  rats  and 
mice,  but  the  result  was  negative. 

However  domestic  and  wild,  mammals  are  not  the  only  hosts  of 
Sarcosporidia ;  these  parasites  are  also  harboured  by  birds.  Thus,  according 
to  Kiihn  (7)  they  are  found  in  the  domestic  fowl,  according  to  Rivolta  (8)  in 
Turdus  Corvus  and  other  birds  ;  according  to  Stiles  (9)  in  North  American 
birds.  Neither  do  the  reptiles  escape.  Bertram  (10)  found  them  in  the  gecko, 
Liihe  (i  i)  in  the  wall-lizard.  It  also  became  evident  that  the  Sarcosporidia 
found  conditions  suitable  to  their  development  not  only  in  the  muscles  but 
also  in  the  connective  tissue.  This  led  to  the  foundation  of  a  new  classification 
[Blanchard  (12)].  Finally,  Sarcosporidia  have  also  been  observed  in  man. 

The  relation  of  these  parasites  to  certain  diseases  of  domestic  animals 
has  been  especially  studied  by  veterinary  surgeons  (13). 

But  little  that  is  fresh  (14)  has  been  added  to  the  results  of  the 
work  of  Bertram  (10)  mentioned  above,  and  on  which  the  following 

1  The  recent  literature  of  the  myxosporidia  also  contains  information  respecting 
the  microsporidia  (Gurley,  Thelohan,  Doflein,  &c.  ;  see  also  Labbe,  Sporozoa,  1899). 


SARCOSPORIDIA 

description  of  the  Sarcosporidia  is  based,  so  that  there  is  still  a  wide  field 
open  for  research  in  regard  to  the  structure  and  development  of  these  parasites 
and  the  manner  in  which  the  hosts  are  infected. 

The   Sarcosporidia   usually   appear   as   elongated,    cylindrical,    or 
fusiform  bodies,  rounded  at  both  extremities  and  of  various  lengths 

and  breadths  (fig.  56)  ;  they  lie  inside  the  striated  muscular 
fibres  which  they  distend  more  or  less.  The  forms  found  in 
the  connective  tissue  are  apparently  parasites  which  originally 
inhabited  the  muscular  fibres,  and  only  on  disintegration  of  the 
fibres  reached  the  connective  tissue,  where  they  grow  to  large  oval 
or  globular  bodies  (fig.  57).  In  fresh  flesh  cut  into  exceedingly  thin 

• 


L. 

FIG.     56. — Longitudinal     section  FIG.    57. — Transverse    section   of 

of   a  muscle    of   the  domestic  pig,  the   muscle   of   a   pig,    with   Sarco- 

with    Sarcocystis    miescheriana  cystis  miescheriana  (Kiihn).     38/1. 
(Kiihn).     30/1. 

slices  they  are  frequently  recognisable,  even  with  the  naked  eyer 
on  account  of  their  yellowish-white  colour  ;  under  the  microscope, 
by  a  refracted  light,  they  appear  to  be  dark  and  coarsely  granular ; 
beginners  will  find  some  difficulty  in  distinguishing  them  from 
other  foreign  bodies,  such  as  dead  and  calcified  encapsulated 
Trichinae,  or  from  cysticerci  that  have  died  and  become  calcified 
in  the  early  stages,  more  particularly  as  the  Sarcosporidia  also 
occasionally  may  become  calcified. 

The  Sarcosporidia  are  always  enveloped  in  a  membrane,  which 
is  probably  formed  at  an  early  stage  ;  in  a  few  cases  it  remains 
thin  and  simple,  in  other  cases  a  so-called  "  rod-like  armature " 
is  exhibited,  which  has  been  variously  described.  From  the  inner 
integument,  which  may  be  homogeneous  or  fibrous,  thick  or  thin, 


THE    ANIMAL    PARASITES    OF    MAN 


there  arise  membranes  in  the  interior  of  the  body  that  form 
anastomosing  partitions,  or  rather  a  system  of  manifold  chambers 
of  various  sizes  that  do  not  communicate  with  one  another 
(fig.  58).  These  chambers  are  occupied  by  sickle  or  bean-shaped 
bodies  (sporozoites),  or  rather  their  stages  of  development  ;  fre- 
quently, however,  they  .are  empty,  and  this  is  particularly  the 
case  in  the  central  chambers  of  the  large  species. 

In   the  youngest   Sarcosporidia   (0-04   mm.   in   length)   from   the 
muscles    of    the    sheep    one    finds,    according    to    Bertram,    small 


FIG.  58.  —  Transverse  section  of  Sarcocystis 
tenella,  Raill.  (from  the  oesophagus  of  Ovis  aries). 
38/1.  (a)  Marginal  chambers  filled  with  spores  ;  (b) 
connective  tissue  of  the  ossophagus  ;  (c)  muscles 
of  the  ossophagus. 


FIG.  59  . — Young 
Sarcocystis  tenella 
of  the  sheep  (0*047 
mm.  in  length) 
(after  Bertram). 


roundish  or  oval  cells  (0*004-0*005  mm.),  the  nuclei  of  which  are 
half  their  size,  and  are  embedded  in  a  granular  and  apparently 
protoplasmatic  mass  ;  in  somewhat  larger,  and  therefore  older,  cylin- 
ders, the  investing  membrane  of  which  already  presents  both  layers, 
the  cells  have  become  larger  (to  0*007  mm.)  and  are  more  sharply 
outlined  from  each  other  (fig.  59).  Taking  their  later  condition 
into  account  they  may  be  considered  as  sporoblasts,  for  their 
nuclei  commence  to  divide  ;  finally  they  become  isolated  within 
the  chambers,  the  dividing  partitions  of  which  originate  from  the 
granular  protoplasm  which  is  present  between  the  sporoblasts  ; 


SARCOSPORIDIA 


the  numerous   bodies   thus    originated    are    nucleated    and  become 

spores  direct. 

The    process    commences    in    the    centre    of    the    cylinders,    arid 

then   progresses   towards   the   extremities,    the   parasites   meanwhile 

increasing   in   size,   and   new   sporoblasts   being   continually   formed 

at   the  extremities   (fig.   60). 

The  spores  vary  in  shape  according  to  the 
species,  but  are  also  of  different  form  in- 
dividually ;  they  are  mostly  kidney-,  bean-  or 
sickle-  shaped,  and  of  a  very  small  size.  They  are 
apparently  surrounded  by  a  membrane,  and  at 
one  extremity  (according  to  the  discovery  of 
L.  Pfeiffer,  confirmed  by  van  Eecke,  Laveran 
and  Mesnil)  contain  an  obliquely  striated  body 
(fig.  61)  understood  to  be  the  pole  capsule, 
while  the  greater  part  of  the  spore  is  taken 
up  by  the  nucleated  sporozoit. 

Several  authors  state  that  they  have  also 
observed  filamentous  appendages  at  one  pole  of 
the  spores,  and  have  seen  two  sorts  of  spores 
in  the  same  Sarcosporidium,  but  these  observa- 
tions require  confirmation. 

The  duration  of  life  of  the  Sarcosporidia 
is  a  comparatively  long  one  ;  the  affected  mus- 
cular fibres  may  remain  intact  and  capable  of 
performing  their  functions  for  a  lone:  time,  but 

FIG.   60. — Termina- 
tion  of   a    Sarcocystis    at  last  they  perish,  if  the  host  lives  long  enough, 

Zptogrof^ptg6  so  that  the  sarcosporidia  of  the  muscles  are 
800/1.  (After  Bertram.)  then  enveloped  only  by  sarcolemma,  and  finally, 
when  this  likewise  disappears,  they  fall  into  the 
intra-muscular  connective  tissue.  In  many  cases  the  sarcosporidia 
die  off  within  their  hosts,  this,  according  to  Bertram,  being  brought 
about  by  a  disintegration  of  the  spores  in  the  central  chambers  ; 
in  other  cases  the  leucocytes  play  a  part  in  the  destruction  of  the 
sarcosporidia,  and  finally,  it  is  a  common  occurrence  for  lime  salts  to 
be  deposited  in  and  around  the  vacant  cylinders. 

The  manner  in  which  the  hosts  become  infected  is  entirely 
unknown,  although  transmission  must  occur  very  frequently,  as  in 
some  places  pigs,  sheep,  mice  and  rats  are  infected  to  a  remark- 
ably high  percentage,  indeed,  not  far  below  100  per  cent.  Young 
animals  also  show  that  they  are  already  infected,  and  perhaps 
infection  only  takes  place  during  youth.  As  most  of  the  hosts 


Il6  THE    ANIMAL    PARASITES    OF    MAN 

are  herbivorous,  .the  idea  of  a  direct  transmission  through  eating- 
infected  flesh  may  be  summarily  dismissed  ;  experiments,  such  as 
the  inoculations  carried  out  by  Kasparek,1  have  also  yielded 
negative  results.  Moreover,  the  spores  have  not  much  power  of 
resistance  ;  for  instance,  they  perish  in  the  gastric  juices. 


FIG.  61. — Spores  of  Sarcocystis  tenella,  Raill.  1000/1.) 
(a)  Fresh  with  the  polar  capsule  ;  (b)  stained  (after  Laveran 
and  Mesnil). 


We  are  still  unacquainted  with  the  manner  in  which  the  enor- 
mous infection  of  the  same  host  comes  to  pass.  That  which 
Pfeiffer  says  on  the  matter  is  altogether  hypothetical.  The  CLASS- 
IFICATION OF  THE  SARCOSPORIDIA  as  proposed  by  R.  Blanchard,  and 
which  was  based  on  their  various  habitats,  can  no  longer  hold  good, 
because  the  same  species  may  occur  in  the  muscles  as  well  as  in 
the  connective  tissue  ;  for  the  present  the  few  species  that  are 
known  may  be  placed  in  one  genus  (Sarcocystis,  R.  Leuck.). 

THE  SARCOSPORIDIA  OBSERVED  IN  MAN. 

(1)  Lindemann  (Ueb.  d.  hyg.  Bdtg.  d.  Gregarinen  in  Dtsche.  Zlschr. 
f.  Staatsarzneikde,  1868)  found  on  the  valves  and  in  the  myocardium 
of    a    person    that    had    died   of    dropsy    certain   brownish   masses, 
3  mm.   in   length  and   1-5  mm.  in  breadth   which    he    regarded   as 
gregarines.      If    these  were   actually  independent  animal   organisms 
it  may  be  suggested  that  they  were  Sarcosporidia. 

(2)  Rosenberg    (Ein    Befund    von     Psorosp.     in     Herzmusk.     d. 
Menschen    in   Ztschr.    /.  Hygiene,   1892,   xi.,    p.    435)   found    a  cyst 
5  mm.  in  length  and  2  mm.  in  breadth  in  a  papillary  muscle  of 
the  valvula  mitralis  of    a  woman,  40   years  of  age,  who  had  died 
from  pleuritis  and  endocarditis.      The  cyst  contained  no  scolex  nor 
booklets   of  taenia  ;   numerous  small   refracting  bodies,   round>  oval 
or    kidney-shaped,    were    found    in    a    daughter    cyst,    as    well    as 
sickle-shaped    bodies.      The   description  hardly   appears  to  indicate 
Sarcosporidia. 

1  It  may  incidentally  be  mentioned  that  the  Sarcosporidia  contain  a  toxin  (sarco- 
cystine)  that  has  a  serious  effect  on  warm-blooded  animals.  More  on  this  subject 
can  be  learned  from  L.  Pfeiffer  and  from  Laveran  and  Mesnil  (De  la  sarcocystine,  toxins 
d.  sarcospor.  In.  C.  R.  soc.  bioL,  Paris,  1899  [10],  vi.  p.  311). 


SARCOSPORIDIA  117 

(3)  Kartulis    observed    Miescher's   cylinders   of   various   sizes   in 
the  liver  (?)  and  in  the  muscular  system,  but  not  in  the  fibres  of 
a  Soudanese  who  had  succumbed  to  multiple  abscesses  of  the  liver 
and  abdominal  muscles.     This  may  be  considered  as  the  first  actual 
case    of    the    occurrence   of    sarcosporidia    in    man    (Kartulis,    Ueb. 
pathog.  Protoz.  b.  Menschen,    in  Ztschr.  f.    Hyg.  u.  Inf.,    1893,   xiii., 
p.   i.     Compare  also  Braun,   M.,   Die   Thier.   Par.   d.    Mensch.,    2nd 
Edit.,   Wrzbg.,    1895,    p.  92.      Braun,   M.,  Z.    York.   d.  Sarcosp.,   b. 
Menschen,  in  C.  /.  B.  P.,  1895,  xviii.,  p.   13). 

(4)  The   case   reported   by   Baraban   and   St.    Remy    ("  Sur   un 
cas   de  tub.    psorosp.   ob.    chez   rhomme"   in   C.   R.   soc.   biol.,   Paris, 
1894   (x.),    I.,   p.   201.     "  Le  parasitisme  d.  Sarcosp.  chez  rhomme" 
in    Bibliogr.    anat.,    1894,    p.    79),    was    at    once    demonstrated    as 
certain.      It    related    to    a   man    who    had    been    executed,    and   in 
the    laryngeal    muscles    of    whom    Sarcosporidia    were  found  ;    the 
length   of    the    parasites    fluctuated    between    0*150    and    1*6    mm., 
their   breadth   between   0*077   and   0*168   mm.     'The   affected   mus- 
cular fibres  were  distended  to  four  times  their  normal  thickness. 


LITERATURE. 

(i)  MIESCHER,  F.     Ueb.  eigenth.  Schlauche  i.  d.  Musk,  einer  Hausmaus  (Bericht  ub. 

d.  Verhandl.  d.  naturf.  Ges.  Basel.,  1843,  v->  P-  J98)- 
<2)  V.  HESSLING.     Histol.  Mitth.  (Z.  f.  w.  Zool.,   1854,  v.,  p.  189). 

(3)  SIEBOLD,  C.  Th.  v.     Addition    (ib.,  p.  199). 

(4)  RAINEY,  G.     Struct,  and  devel.  of  Cyst.  cell,  as  found  in  the  Muscles  of  the  Pig 

(Transact.  R.  Phil.  Soc.,  1858,  cxlvii.,  p.  in). 

{5)  LEUCKART,  R.     Die  menschl.  Parasit.  (i  edit.,  i  vol.,  1863,  p.  237). 
<6)  MANZ,  W.      Beitr.   z.    Kenntn.   d.  Miesch.   Schl.   (Arch.   mikr.    Anat.,    1867,  iii., 

P-  345)- 

(7)  KiiHN.     Mitth.  landw.  Inst.  Halle,  1865,  p.  68. 

(8)  RIVOLTA.     Dei  parass.  veget.,  Torino,  1873,  and  Giorn.  an.,  fis.  e.  pat.  d.  anim., 

1874,  vi.,  p.  25). 

(9)  STILES,  CH.  W.     Notes  on  par.  18,  Pres.  of  Sarcosp.  in  birds  (U.S.  Dep.  of  Agric. 

Bur.  of  anim.  ind.  Bull.,  No.  3,  Washington,  1893,  P-  79)- 
<io)  BERTRAM,   A.     Beitr.   Z.    Kenntn.   d.    Sarcosp.     In.   Diss.    Rostock,    1892    (Zool. 

Jahrb.  Abth.  f.  Morphol.,  v.). 

<ii)  LUHE,  M.     Ergebn.  d.  neuer.  Sporoz.-Forsch.     Jena,  1900,  p.  89. 
{12)  BLANCHARD,  R.       Sur  un    nouv.  typ.  d.  Sarcosp.    (C.  R.  Ac.    sc.  Paris,  c.    1885, 

P-  I599)-     Note  sur  les  Sarcosp.  et  sur  un  ess.  d.  classif.  de  ces  sporoz.  (Bull. 

soc.  zool.  France,  1885,  x.,  p.  244). 

(13)  RIECK,    V.     Sporozoen  als  Krankheitserr.   (Dtsche.   Ztsch.  f.  Thiermed.  u.  vergl. 

Path.,    1889,  xiv.,  p.   75). 

(14)  LEISERING  and  WINKLER.     Psorosp.-Krkht.  beim  Schaf  (Ber.  iib.  Vet.  Wes.  Kgr. 

Sachsen,  1865  '    Virchow's  Arch.  f.  patho.  An.,  1865,  xxxvii.,  p.  431). 
<i5)  DAMMANN,  C.     Psorosp.-Krkht.  beim  Schaf  (ibid.,  1867,  xli.,  p.  283). 
(16)  SIEDAMGROTZKY,  O.     Psorosp.  i.  d.  Musculatur  d.  Pferde  (Wochschr.  f.  Thierhlk. 

u.  Viehzucht,   1872,  xvi.,  p.  97). 
{17)  SCHNEIDEMUHL,  G.  Ueber  Sarcosp.  (Thiermed.  Vortr.  III.,  n,  Lpzg.  1897). 

(18)  PLUYMERS,   L.      Des  sarcosp.  et  de  leur  role  dans  la  pathog.  d.  myositis  (Arch. 

med.  exp.  et  d'an.  pathol.,  1896,  p.  761  ;    C.  f.  B.,  P.  u.  I.  [i],  xxii.,  p.  245). 

(19)  PFEIFFER,  L.     Die  Prot.  als  Krankhtserr.     II.  edit.     Jena,  1891.     Unters.  iib.  d. 

Krebs.      Jena,  1893. 


Il8  THE    ANIMAL    PARASITES    OF    MAN 

(20)  EECKE,    J.    VAN.       Sarcosporidien    (Geneesk.    Tijdsch.    v.     Nederl.-Indie,     1892, 

xxxii.  ;    Jaarsverl.  Labor,  path.  An.  en  Bact.   te  Weltevreden  [1892],  Batavia, 

1893)- 

(21)  PIANA,  G.  P.     Fasi  evolut.  d.  Sarcosp.  (La  clinica  veter.    1896,  p.   145.     C.  f.  B., 

P.  u.  I.  [i],  xx.,  p.  39). 

(22)  LAVERAN  and  MESNIL.     Morph.  d.  Sarcosp.  (C.  R.  soc.  biol.  1899  [10],  vi.,  p.  245), 

APPENDIX  TO  THE  SPOROZOA. 

After  bacteriology  had,  through  R.  Koch,  attained  unforeseen  import- 
ance, the  living  agents  of  a  number  of  the  so-called  infectious  diseases  of  man 
and  domestic  animals  were  discovered,  but  the  participation  of  living  organisms 
in  the  causation  of  other  diseases  as  well  as  neoplasms  was  denied.  The 
character  of  these  disturbances,  however,  led  investigators  to  conjecture  that 
living  organisms  were  also  to  blame  for  their  causation,  and  to  search 
for  them.  Although  investigations  were  instituted  by  various  persons,  it 
cannot  be  denied  that  the  entire  question  was  first  brought  forward  by  the 
works  of  L.  Pfeiffer  in  Weimar.  Starting  with  the  search  for  the  specific 
agent  of  smallpox,  this  author  with  untiring  zeal  pursued  the  study  of  the 
parasitical  protozoa,  and  his  publications,  independent  of  many  discoveries  for 
which  science  is  indebted  to  him,  aroused  much  interest,  and  inspired,  directly 
and  indirectly,  that  impetus  which  has  led  to  so  many  important  discoveries. 
Of  course  many  hopes  and  expectations  have  remained"  unfulfilled,  although 
they  appeared  to  be  justified,  and  the  investigations,  especially  directed 
to  the  discovery  of  the  agents  of  malignant  neoplasms,  have  as  yet  had 
no  favourable  results  and  are  still  a  matter  of  dispute.  Now,  as  formerly, 
the  opinions  of  parties  are  strongly  opposed  to  each  other,  that  which  appears 
to  one  person  to  be  Blastomycetes  or  Myxomycetes,  others  declare  to  be 
Sporozoa  or  other  primitive  animals,  whereas  still  others  declare  that  the 
same  formations  are  the  degeneration  products  of  cells. 

However  necessary  a  knowledge  of  the  works  and  opinions  of  his 
predecessors  may  be  to  the  investigator  of  this  difficult  subject,  the  less 
it  appears,  under  the  present  circumstances,  to  be  necessary  to  enter  here 
on  to  debated  ground.  It  is  to  be  hoped,  however,  that  the  time  is  not  far 
distant  that  will  yield  suitable  methods  for  the  attainment  of  more  certain 
results. 

Class  IV.     Infusoria. 

The  bilaterally  symmetrical  body  of  the  infusoria  is  enveloped 
in  a  cuticle  which  has  numerous  openings  for  the  passage  of  the 
cilia.  Most  kinds  have  a  fixed  shape,  whilst  changes  in  the  form 
of  others  are  brought  about  by  the  contractions  of  the  body  sub- 
stance. The  latter  exhibits  the  hyaline  ECTOSARC,  in  which 
contains  numerous  vacuoles.  The  CILIA,  the  various  arrangement 
MYOPHANES  and  occasionally  also  TRICHOCYSTS  (minute  spindle- 
shaped  bodies)  appear,  and  the  granular  ENTOSAR'C  which  frequently 
of  which  supplies  the  principle  on  which  this  class  is  divided,  are 
always  processes  of  the  ectosarc  ;  their  form  varies ;  they  may  be 


INFUSORIA 

hair-like,  or  more  '  rarely  thorn-like,  spur-like,  or  hook-shaped ; 
undulating  membranes  also  occasionally  occur. 

With  the  exception  of  some  of  the  parasitical  species,  an  oral 
cavity,  PERISTOME  or  CYTOSTOME,  is  always  present  ;  it  is  fre- 
quently beset  with  longish  cilia  or  provided  with  undulating  mem- 
branes, which  help  to  engulf  the  food  ;  frequently  also  there  is  an 
anal  aperture  (cytopyge)  generally  placed  at  the  opposite  pole.  A 
CYTOPHARYNX  clothed  with  cilia  or  supported  by  ligaments  is  joined 
on  to  the  peristome.  Vacuoles  form  round  the  ingested  food, 
and  in  many  species  a  constant  rotation  goes  on  in  the  endo- 
sarc.  Frequently  one,  sometimes  two,  contractile  vacuoles  are 
present,  the  frequency  of  the  pulsations  of  which  depends  on  the 
surrounding  temperature.  Sometimes  there  are  in  the  plasma  special 
conducting  channels  to  the  vacuoles  or  outlet  channels  leading  to 
the  exterior. 

There  is  almost  in  every  case  a  LARGE  NUCLEUS  (macronucleus), 
and  lying  close  up  to  it  a  SMALL  NUCLEUS  (micronucleus) ;  the  form 
of  the  large  nucleus  varies  exceedingly  according  to  the  species. 
Numerous  nuclei  are  of  rare  occurrence  (as  in  Opalina,  which 
lives  in  the  terminal  gut  of  amphibians,  and  is  also  distinguished 
by  the  absence  of  an  oral  aperture). 

Reproduction  is  effected  by  binary  fission  ;  less  commonly,  after 
encystment,  by  multiple  division,  or  by  budding.  The  divisions 
can  be  jnany  times  repeated,  but  finally  cease,  and  then  the  con- 
jugation of  two  specimens  brings  about  a  regeneration,  particularly 
of  the  nuclei.  Numerous  examinations  (Butschli,  Hertwig,  Maupas) 
have  demonstrated  the  fact  that  after  two  individuals  have  joined 
by  homologous  parts  of  the%  body,  the  micronucleus  separates  from 
the  macronucleus,  becomes  larger  and  divides  twice  by  the  karyo- 
kinetic  process,  so  that  four  micronuclei  are  present  in  each  one  of 
the  two  individuals  forming  the  couple  (gamete).  Three  of  these 
nuclei  perish  and  become  absorbed,  the  fourth  gradually  shifts  to 
the  connecting  bridge  of  the  protoplasm,  which  has  originated  by 
absorption  of  the  cuticle  at  the  point  of  contact  of  the  gametes  ; 
and  changes  half  of  its  substance  for  half  of  the  substance  of  the 
fourth  micronucleus  of  the  other  gamete  ;  a  new  nuclear  body  is 
thus  formed  and  divides,  usually  twice,  in  each  gamete.  Of  the 
segments  thus  originated  one  becomes  a  micronucleus,  and  one 
or  several  of  the  others,  as  the  case  may  be,  form  or  amalgamate 
into  a  new  macronucleus,  the  old  macronucleus  usually  perishes 
or  becomes  absorbed  towards  the  termination  of  the  conjugation. 
Usually,  sooner  or  later,  the  two  gametes  separate  and  again  increase 


120  THE   ANIMAL   PARASITES   OF   MAN 

independently  by  segmentations  until  a  series  of  segmentations  are 
again  followed  by  conjugation.  I  cannot  here  go  into  the  theoretical 
signification  of  conjugation  ;  only  this  may  be  remarked,  that  the 
macronucleus  plays  no  part  in  it,  but  governs  entirely  the  meta- 
bolism of  an  infusorian,  whereas  the  micronucleus  is  essentially  a 
sexual  nucleus  from  which  macro-  and  micro-  nuclei  are  produced 
again  and  again. 

Encystment  amongst  the  infusoria  is  very  general,  and  is 
essentially  a  means  of  protection  when  the  waters  dry  up  ;  no 
doubt  these  cysts  are  frequently  carried  long  distances  by  the 
wind,  which  explains  the  wide  geographical  distribution  of  most 
species.  Frequently,  also,  reproduction  takes  place  in  the  encysted 
condition. 

Some  infusoria  live  a  free  life,  others  are  stationary,  the  latter 
form  colonies  in  fresh  as  well  as  in  salt  water  ;  numerous  species 
are  parasites  of  various  kinds  of  the  lower  and  higher  animals,1 
and  a  few  also  are  parasitic  in  man. 

The  Prague  zoologist,  v.  Stein,  introduced  a  classification  of  the 
infusoria  that  has  been  almost  universally  adopted.  It  is  founded 
on  the  different  position  of  the  cilia  on  the  body  ;  though,  no 
doubt,  very  artificial,  it  is  a  convenient  system.  Biitschli  has  com- 
piled a  better  one  (Bronn's  Cl.  u.  Ordn.  d.  Thierr.,  vol.  L,  Pro- 
tozoa, Part  3,  Infusoria).  But  for  our  purpose  Stein's  system  is 
sufficient  :— 

Order  i.     Holotricha,  infusoria  with  cilia  that  a're  evenly  distributed  over 

the  entire  body. 
Order  2.     Heterotricha    ciliated    all    over   like    the    Holotricha,   but    have 

stouter  cilia  about  the  peristome. 

Order  3.     Hypotricha,  ciliated  only  on  the  ventral  surface. 
Order  4.     Peritricha,  with  only  a  ring  of  spiral  cilia,  mostly  stationary. 

The    infusoria    observed  in    man    belong    to  the    order    of    the 

Heterotricha . 


Genus  i.     Balantidium,  Clap,  et  Lachm. 

Heterotrichous  infusoria  of  oval  or  sac-like  form  and  almost  circular  on 
transverse  section  ;  the  anterior  extremity  narrowed,  the  posterior  end 
broad  and  rounded  off,  or  also  narrowed  ;  the  peristome  starting  at  the 


1  I  may  briefly  state  that  numerous  peculiarly-shaped  species  live  in  the  stomach 
of  ruminants,  others  in  the  colon  of  horses  ;  several  species  are  found  in  the  rectum 
of  frogs  and  toads  ;  others,  again,  on  the  surface  of  the  bodies  of  fishes  ;  and  various 
other  species  find  the  conditions  for  their  existence  in  and  on  the  bodies  of  invertebrate 
animals. 


BALANTIDIUM    COLI 


121 


.anterior  end  is  there  broadest  and  becomes  narrower  as  it  obliquely  approaches 
more  or  less  towards  the  posterior  extremity  ;  there  are  coarse  cilia  along 
the  entire  left  border  and  the  front  part  of  the  right  border  ;  longitudinal 
striation  distinct  and  regular  ;  there  are  two  contractile  vacuoles  to  the 
right,  and  occasionally  also  two  or  more  to  the  left.  The  anus  has  a 
terminal  position.  Macronucleus  oval  or  horse-shoe  shaped,  micronucleus 
contiguous.  The  movement  is  always  darting.  The  cysts  are  globular 
or  oval.  Parasitic  in  the  terminal  gut  of  human  beings  and  pigs,  in 
amphibians  and  in  the  body  cavity  of  polychaetic  annelida. 


i.  Balantidium  coli  (Malmst.),  1857. 
Syn.  Paramcecium  coli,  Malmsten,   1857. 

Body  oval,  0*06-0- 1  mm.  in  length  (up  to  0*2  mm.  according 
to  Janowski),  and  0-05-0-07  mm.  in  breadth.  The  peristome  is 
funnel-shaped  or  contracted,  the  anterior  end  being,  accordingly, 
•either  broadened  or  pointed.  The  ecto-  and  endo-  sarc  are  distinctly 


FIG.  62. — Balan- 
iidium  coli.  (a) 
Nucleus ;  (b)  vacu- 
ole  ;  (c)  peristom 
(d)  bolus  of  food 
(after  Leuckart). 


1 


5«B 


a.  b. 

FIG.  63. — Balantidium  coli,  free  and  en- 
cysted ;  (a)  anus  ;  (n)  nucleus  ;  (b)  bolus  of 
food  (after  Casagrandi  and  Barbagallo). 


separate,  the  latter  granular,  and  containing  drops  of  fat  and 
mucus,  granules  of  starch,  bacteria,  and  occasionally  also  red  and 
white  blood  corpuscles  ;  there  are  usually  two  contractile  vacuoles, 
sometimes  even  more.  The  anus  opens  at  the  posterior  extremity. 
The  macronucleus  is  bean-  or  kidney-  shaped,  rarely  oval ;  the  micro- 
nucleus  globular. 

It  lives  in  the  large  intestine  of  man  and  in  the  rectum  of  the 
domestic  pig  ;    it  propagates   by   transverse   division,  but   conjuga- 


122  THE   ANIMAL   PARASITES   OF   MAN 

tion  and  encystment  are  known  to  take  place  ;x  transmission  to 
other  hosts  is  effected  during  the  encysted  stage. 

Balantidium  coli  was  discovered  by  Malmsten  in  1857  m  a 
man  aged  35  years,  who  had  two  years  previously  suffered  from 
cholera,  and  since  then  had  been  subject  to  diarrhoea ;  the 
examination  revealed  an  ulcer  in  the  rectum  above  the  mid 
sphincter  ani,  in  the  sanguineous  purulent  secretion  of  which 
numerous  Balantidia  were  swimming  about.  Although  the  ulcer 
was  made  to  heal,  the  diarrhoea  did  not  cease  and  the  stools 
contained  numerous  balantidia,  the  number  of  which  could  only 
be  decreased  by  extensive  enemas  of  hydrochloric  acid. 

The  second  case  related  to  a  woman  who  was  suffering  from 
severe  colitis,  and  who  died  ten  days  after  admission.  The  mal- 
odorous, watery  evacuations  contained  innumerable  balantidia  in 
addition  to  pus,  and  at  the  autopsy  the  anterior  portion  of  the 
large  intestine  was  found  to  be  their  habitat. 

Subsequently  this  parasite  has  often  been  observed  in  human 
beings,  and  according  to  Shegalow's  compilation  63  cases  have  been 
recorded.  These  occurred  as  follows  :  24  cases  in  Russia,  15  cases 
in  Scandinavia,  7  cases  in  Finland,  6  cases  in  Cochin  China,  5  cases 
in  Italy,  3  cases  in  Germany,  2  cases  in  the  United  States,  and 
i  case  in  the  Sunda  Islands. 

In  addition  5  more  cases  came  under  observation  in  Konigs- 
berg,  Prussia  (Collmann),  one  was  incidentally  mentioned  by 
Maggiora  as  occurring  in  the  Province  of  Alexandria,  and  one 
case  occurred  in  Tomsk  (Solowjew). 

In  the  greatest  'majority  of  the  cases  the  patients  suffered 
from  obstinate  intestinal  catarrh^  which  did  not  always  cease  even 
after  the  balantidia  had  disappeared  ;  whereas,  on  the  other  hand, 
balantidia  have  occasionally  still  been  found  to  be  present,  though 
in  small  numbers,  after  the  catarrh  has  been  cured.  Most  authors, 
nevertheless,  do  not  regard  balantidia  as  the  primary  cause  of  the 
various  diseases  of  the  large  intestine,  which  often  commence  with 
the  development  of  ulcers,  but  they  consider  that  they  may 
aggravate  these  diseases  and  render  them  obstinate.  According  to 

1  According  to  Gourvitch  ("  Bal.  coli.  Darmk.  d.  Menschen,"  Russ.  Arch.  /.  Path., 
klin.  Med.  u.  Pact.,  St.  Petersb.,  1896),  the  conjugated  balantidia  are  supposed  to  amal- 
gamate with  each  other  and  form  oval  cysts  two  or  three  times  the  size  of  the  free 
creatures,  and  to  divide  into  numerous  globules  within  the  cystic  membrane  ;  the 
process,  however,  has  hitherto  not  been  observed.  The  supposed  balantidium  cysts 
appeared  in  two  patients  after  the  administration  of  anthelminthic,  and  who  were 
simultaneously  suffering  from  Bothriocephalus  latus ;  it  therefore  appears  to  me, 
according  to  the  description,  that  in  reality  these  forms  were  actually  abnormally 
large,  possibly  swollen,  young  eggs  of  the  tapeworm  mentioned. 


BALANTIDIUM   COLI  123 

Solowjew,  however,  the  parasites  penetrate  the  intestinal  wall,  and 
give  rise  to  ulcerations  which  may  extend  deeply  into  the  subserosa  ; 
this  author  states  that  he  has  also  seen  them  in  the  blood  and 
lymphatic  vessels  of  the  intestinal  wall.  Strong  and  Musgrave  (Bull. 
Johns  Hpk.  Hosp.,  1901,  xii.)  have  made  similar  observations,  as 
also  has  M.  Askanazy  (Vortrag.  i.  d.  biol.  Sect.  d.  Phys.  Ges. 
Konigsberg,  Pr.,  1902).  According  to  Stokvis,  Balantidium  coli 
occurs  also  in  the  lung  ;  at  all  events  this  author  states  that  he 
found  one  living  and  several  dead  paramaecia  (?)  in  the  sputum 
of  a  soldier  returned  from  the  Sunda  Islands,  and  who  was 
suffering  from  a  pulmonary  abscess. 

Since  Leuckart  confirmed  the  frequent  presence  of  Balantidium 
coli  in  the  rectum  of  pigs,  and  corresponding  observations  were 
made  in  other  countries,  the  pig  is  universally  considered  to  be  the 
means  of  the  transmission  of  balantidium  to  man.  The  encysted 
stages  alone  can  subserve  transmission,  because,  according  to 
all  observations,  the  free  parasites  have  a  Very  small  power  of 
resistance ;  they  even  perish  when  the  faeces  have  become  cool, 
they  cannot  live  in  ordinary,  or  slimy,  or  salt  water  ;  and  as  they 
are  killed  by  acids  even  when  much  diluted,  it  follows  that  they 
could  not  pass  through  the  normal  stomach  alive  except  under 
the  most  exceptional  circumstances.  The  pigs,  in  whose  intes- 
tines the  balantidium  appears  to  cause  no  disturbances,  evacuate 
numerous  encysted  balaritidia  with  the  faeces,  and  their  occasional 
transference  to  man  brings  about  their  colonisation  there,  but 
apparently  only  when  a  disease  of  the  colon  already  exists.  No 
colonisation  takes  place  in  healthy  persons,  as  has  been  demon- 
strated by  Grassi  and  Calandruccio  from  experiments  made  on 
their  own  persons. 

Experimental  transmission  of  the  free  parasites  to  animals  (per 
os  or  per  anum)  yielded  negative  results,  even  in  the  case  of  pigs ; 
only  Casagrandi  and  Barbagallo  had  positive  (as  well  as  negative) 
results  ;  they  employed  healthy  young  cats,  or  cats  in  which 
catarrhal  entero-colitis  had  been  artificially  induced  (and  which  in 
other  experiments  is  apt  to  cause  the  death  of  the  animals  experi- 
mented upon  in  about  six  or  seven  days),  or  finally  cats  that  had 
dilatation  of  the  rectum  with  alkaline  reaction  of  the  faeces.  The 
experiment  to  infect  three  healthy  cats  by  injecting  human  fieces 
containing  balantidium  in  the  rectum  proved  negative,  in  so  far 
as  the  faeces  of  the  experimental  animals  had  an  acid  reaction  and 
contained  no  balantidia,  but  at  the  autopsy  performed  after  eight 
days  a  few  ENCYSTED  parasites  were  found  in  the  mucus  of  the 


124  THE   ANIMAL    PARASITES    OF    MAN 

ileum.  In  the  case  of  four  cats  suffering  from  entero-colitis,  into 
which  human  faeces  containing  balantidia  were  introduced  per  os, 
balantidium  cysts  were  found  in  the  faeces  three  days  after  the 
last  ingestion  ;  great  numbers,  moreover,  were  found  in  the  caecum 
and  the  posterior  part  of  the  small  intestine  at  the  autopsy  of 
the  animals  which  died  about  eight  days  after  the  commencement 
of  the  experiment  ;  actual  colonisation,  therefore,  was  not  achieved 
in  either  series  of  experiments.  Free  or  encysted  balantidia  of 
pigs  were  used  for  further  experiments.  The  experiments  proved 
negative  when  faeces  containing  cysts  were  injected  into  the  rec- 
tum of  healthy  cats  (three  experiments),  or  cats  (two)  suffering 
from  spontaneous  intestinal  catarrh,  or  when  such  material  was 
introduced  per  os  into  three  healthy  cats.  In  the  case  of  two 
cats  with  intestinal  catarrh  artificially  produced,  a  small  number 
of  the  non-encysted  balantidia  injected  into  the  rectum  remained 
alive ;  larger  quantities  of  faeces  containing  encysted  balantidia 
were  introduced  into  two  other  cats  affected  with  the  same  com- 
plaint ;  these,  certainly,  did  not  appear  in  the  fasces,  but  small 
numbers,  free  and  alive,  were  found  in  the  caecum.  Similarly 
encysted  balantidia  were  introduced  into  two  cats  with  dilated 
rectum,  and  whose  faeces  had  an  alkaline  reaction  ;  in  these  cases 
also  no  parasites  appeared  in  the  faeces,  but  three  and  five  days 
later,  when  the  two  animals  were  examined,  a  very  small  number 
were  discovered  free  in  the  large  intestine. 

These  experiments  teach  us  that  human  faeces  and  the  faeces 
of  pigs  have  a  different  effect  on  cats,  moreover,  that  they  are 
neither  pathogenetic  to  these  animals  nor  capable  of  influencing 
intestinal  diseases,  artificial  or  spontaneous,  and  finally  that  even 
when  not  encysted  they  pass  through  the  stomach  of  cats  unin- 
jured when  introduced  with  large  quantities  of  faeces  of  an  alkaline 
reaction.  It  stands  to  reason  that  this  mode  of  infection  cannot 
be  considered  as  a  means  of  transmission  to  man. 

LITERATURE. 

MALMSTEN,    P.    H.     Infusorien   als   Intestinalthiere   b.   Mensch.    (Virch.    Arch.,    1857, 

xii.,  p.  302.) 
SHEGALOW,  J.  P.     Ein  Fall  v.  Bol.  coli  bei  einem  5  jahr.  Madch.  (Jahrb.  f.  Kdrhlkde., 

1899,  xlix.,  p.  425)- 
JANOWSKI,  W.     Ein  Fall  v.  Bol.  coli  im  Stuhl  (Ztschr.  f.  klin.  Med.,  1897,  xxxii.,  p. 

415).     (A  complete  list  of  the  literature  is  given  by  Janowski,  Shegalow  and 

Solowjew.) 

COLLMANN,  B.      5  Falle  v.  Bol.  coli  i.  Darm  d.  Mensch.  In.  Diss.  Kgsbg.,  1900. 
MAGGIORA,  A.     Micr.   u.  bact.   Beob.  wahr.  ein.  epid.  dys.  Dickdarmentziind.   (C.  f. 

B.  u.  P.,  1892,  xi.,  p.   181). 
SOLOWJEW.     Bol.  coli  als  Erreg.  chron.  Durchf.  (C.  f.  B.,  P.  u.  I.,  1901  [i],  xxix.,  pp. 

821,  849). 


BALANTIDIUM    MINUTUM 


125 


STOKVIS,  B.  J.     Paramecium  in  sputa  (Nederl.  Tijdsch.  voor  Geneeskde.,  1884  [2],  xx. 

LEUCKART,  R.     Die  menschl.  Par.,   ist  edit.,  ist  vol.,  1863,  p.  147. 

GRASSI,    B.     Signif.   patol.   d.   prot.  par.  dell'uomo  (Atti  Accad.   d.   Lincei    Rendic., 

1888  [4],  iv.,  Sem.  i,  p.  86). 
CASAGRANDI,  O.,  and  P.  BARBAGALLO.     Bol.  coli  s.  Param.  coli.  Catania,  1896.     8°. 


2.     Balantidium  minutum,  Schaudinn,   1899. 

Body  of  oval  form,  anterior  extremity  pointed,  posterior 
extremity  broad  and  rounded  off.  Length  0*02-0-032  mm.,  and 
0-014-0-02  mm.  in  breadth  ;  the  peristome,  fissure-like,  extends  to 
the  centre  of  the  body  ;  the  right 
lateral  border  of  the  peristome  is 
beset  with  cilia  the  same  length  as 
those  of  the  body,  the  left  side  ter- 
minates in  a  thin  hyaline  membrane 
that  extends  towards  the  back  and 
flaps  over  the  right  border  of  the 
peristome.  A  row  of  longer  and 
stronger  cilia  on  the  left  border  of 
the  peristome.  The  cuticle  is  light, 
refracting,  the  ectosarc  hyaline,  the 
endosarc  granular,  with  numerous 
food  vacuoles. 

A  single  contractile  vacuole  lies 
dorsally  on  the  left  in  the  posterior 
extremity.  The  macronucleus, 


I 


which     is     always     globular,     lies     in      almost    as    large     as     the    granulated 
f      ,  ,  ,  macronucleus  in  front   of   it  ;    close  to 

the    centre    of    the    body    and    is     the  latter  is  the  micro-nucieus  ;   the 

0-006-0-007    mm.    in    diameter  ;     the      food    vacuoles    are    in     the     endosarc 

(after  Schaudinn). 

micronucleus,    close  in  front  of  it, 

only  measures  o-ooi  mm.      The  cysts  are  oval. 

These  parasites  were  found  in  masses  in  the  evacuations  of  a 
man  aged  30,  who  was  born  in  Germany  and  had  repeatedly 
travelled  between  Hamburg  and  North  America,  where  he  made 
long  stays.  The  patient  came  to  the  Charite  in  Berlin  to  seek 
advice  for  constipation  alternating  with  diarrhoea  accompanied  by 
abdominal  pain. 

A  second  case  (termed  Colpoda  cucullus  by  Schulz)  was 
observed  in  a  patient  in  the  same  institution. 

As,  in  both  cases,  the  parasites  only  appeared  during  the 
diarrhoea,  and  disappeared  as  soon  as  the  faeces  had  assumed  a 
normal  consistency,  or  could  only  be  demonstrated  in  a  few 


126  THE   ANIMAL    PARASITES    OF    MAN 

encysted  specimens,  it  may  be  assumed  that  the  small  intestine 
or  the  duodenum  is  their  habitat.1 

Genus  2.     Nyctotherus,  Leidy,  1849. 

Flat,  heterotrichous  infusoria,  kidney-  or  bean-  shaped.  The  peristome 
commences  at  the  anterior  pole  of  the  body  and  extends  along  the  concave 
side  up  to  the  middle,  where  the  oral  aperture  is  situated.  The  cyto- 
pharynx  runs  in  an  oblique  direction  and  is  more  or  less  bent.  The 
anus  is  at  the  posterior  extremity,  where  a  single  contractile  vacuole  is  also 
situated.  The  macronucleus  is  almost  in  the  centre  of  the  parasite.  This 
species  lives  parasitically  in  the  intestine  of  amphibians,  insects  and 
myriapods,  and  one  species  is  also  found  in  man. 

Nyctotherus  faba,  Schaudinn,  1899. 

The  body  is  bean-shaped,  and  a  little  flattened  dorso-ventrally, 
o*O26-o'O28  mm.  in  length,  croiG-o'oiS  mm.  in  breadth,  O'oio- 

O'0i2  mm.  in  thickness.       The 
i 

peristome  is  on  the  right  bor- 
der and  extends  to  the  middle  ; 
at  the  left  there  are  large  adoral 
cilia ;  the  cilia  on  the  right 
border  not  being  larger  than 
those  on  the  body  ;  the  cyto- 
pharynx  is  short,  slightly  bent 
and  turned  backwards.  The 
contractile  vacuole  is  large, 
globular,  situated  at  the  pos- 
terior extremity,  and  its  con- 
tents are  voided  through  the 
anus  at  its  left.  The  macro- 
nucleus  is  in  the  centre  of  the 

FIG.  65. — Nyctotherus  faba,  Schaud.     From   ,  . ,     .          TIT  /- 

life  (after  Schaudinn).  body  ;       it    IS      globular     (O'OO6- 

0*007    mm.    in    size),    and    has 

four  or  five  largish  collections  of  chromatin  ;  the  micronucleus 
lies  close  to  it,  and  is  globular  or  somewhat  elongated  (o'OOi-O'ooi5 
mm.).  Cysts  oval. 

This  species  has  hitherto  only  been  seen  once  in  the  same 
patient  in  whom  Balantidium  minutum  was  discovered.2 

1  Jakoby,  M.,  and  F.  Schaudinn,  "  Ueb.  2  neu  Inf.  i.  Darm  d.  Mensch."  (C.  /.  B., 
P.  u.  I.,  1899,  xxv.,  p.  487)  ;  Schulz,  "  Colpoda  cucullus  im  Darm  d.  Mensch."  (Berl. 
klin.  Wchschr.,  1899,  No.  16,  p.  353). 

-  For  literature  see  above,  Balantidium  minutum. 


PLATYHELMINTHES  127 

APPENDIX  TO  THE  INFUSORIA. 

In  order  to  guard  against  renewed  ERRORS  it  must  be  mentioned  that 
little  objects  moving  by  means  of  cilia  have  repeatedly  been  found  in  the 
sputum  or  nasal  mucus  in  diseases  of  the  respiratory  passages,  and  being 
regarded  as  genuine  parasites  have  been  brought  into  connection  with 
these  diseases.  The  very  irregular  and  varied  form  of  these  bodies,  their 
rapid  and  peculiar  disintegration,  and  the  origin  of  the  fluids  in  which 
they  are  found,  should  have  guarded  from  error.  These  little  bodies  are 
nothing  but  loosened  ciliated  cells  from  the  trachea,  the  bronchial  tubes 
or  the  nose,  which  move  with  the  assistance  of  the  cilia  for  some  time, 
though  this  does  not  prove  their  independent  nature.  To  this  category 
belong  Asthmatos  ciliaris,  Salsb.,1  Deichler's  protozoa  of  whooping  cough,- 
as  well  as  Kurloff's  parasites  of  whooping  cough.3 

G.  Lindner,  of  Cassel,  has  also  become  the  victim  of  repeated  errors  and 
mistakes  in  spite  of  all  protests  ;  he  never  tires  of  hunting  for  certain 
peritrichous  infusoria  (non-pedunculated  vorticella),  and  seeks  to  bring 
them  into  connection  with  the  most  various  diseases  of  man  and  beast, 
and  he  even  tries  to  connect  them  with  the  sarcosporidia  of  pigs.  It  is 
not  necessary  for  the  author  of  this  book  to  go  further  into  the  relation  of 
these  mistakes.4 


B.  PLATYHELMINTHES,    or   Flat    worms. 

Bilaterally  symmetrical  worms,  the  form  of  which  is  blade  or  tape- 
like,  rarely  cylindrical,  and  whose  primary  body  cavity  (segmentation 
cavity)  is  mostly  filled  up  by  a  mesenchymatous  tissue  (parenchyma).  The 
mouth  is  either  situated  at  the  anterior  end  of  the  body,  or  is  shifted 
more  or  less  backwards  onto  the  flat  abdominal  surface.  The  alimentary 
canal  consists  of  a  short  fore-gut,  which  is  frequently  provided  with  a 
muscular  pharynx,  and  of  a  simple  forked  or  branched  mid-gut  ;  there  is  neither 
a  hind-gut  nor  an  anus  ;  in  one  group  the  Cestodes  the  alimentary  canal  has 
entirely  disappeared. 

The  INTEGUMENT  OF  THE  BODY  consists  either  of  a  ciliated  epithelium  of  only 
one  layer  (Turbellaria),  or  of  a  cuticle  and  of  glandular  cells  sunk  into  the 
parenchyma,  which  is  termed  a  subcuticular  layer  (Cestodes,  Trematodes). 
The  musculo-dermal  layer  consists  of  annular,  longitudinal,  and  even  diagonal 
fibres,  whereas  the  parenchyma  is  traversed  by  dorso-ventral  fibres. 

The   central    NERVOUS    SYSTEM,    which    is   embedded    in    the    parenchyma 


1  Salisbury,  J.  H.,   "  Infus.  Catarrh  and  Asthma  ;    discovery  of  the  Cause  of  one 
form  of  Hay  Fever,  &c."   (Ztschr.  f.  Parasitenkde.   (Hallier),  iv.,  [1873],   1875,  p.  6); 
Cutter,  E.,  "  Rhizop.  a  Cause  of  Disease"  (Virginia  Med.  Monthly,  v.,  1878,  p.  605, 
and  vi.,  1879,  p.  28);    Leidy,  J.,   "  Asthm.  ciliaris,  is  it  a  Parasite?  "  (Amer.  Journ. 
Med.  Sc.,  1879,  Ixxvii.,  p.  85). 

2  Deichler,  C.,  "  Ueb.  paras.  Prot.  im  Keuchhustenauswurf  "  (Z.  f.  w.  Z.,  1885,  xliii., 
p.  144,  and  1889,  xlviii.,  p.  303). 

3  Kurloff,  M.,  "  Keuchhusten-Parasiten  "  (C.  f.  B.,  P.  u.  I.  [i].  xix.,  1896,  p.  513). 

4  According  to  a  written  statement,   Schaudinn    has  repeatedly  found   vorticella 
with  lively  movements  in  freshly-evacuated  faeces,  but  always  only  after  water  enemas. 


128  THE   ANIMAL    PARASITES    OF    MAN 

of  the  body,  consists  of  cerebral  ganglia,  united  together  in  the  shape  of 
dumb-bells,  and  of  two  or  several  MEDULLARY  FASCICULI  forming  often 
anastomoses.  Organs  of  sense  usually  occur  only  in  the  free-living  species,, 
more  rarely  during  the  free-living  stages  of  a  few  parasitic  species  and  in  a 
few  ectoparasites. 

[In  Platyhelminthes  simple  eye-spots  frequently  occur,  and  in  a  few 
an  auditory  vesicle. 

BLOOD-VESSELS  and  definite  RESPIRATORY  ORGANS  are  lacking  [except  in 
N ' emertinea] ;  the  EXCRETORY  APPARATUS  (formerly  also  termed  water-vascular 
system)  is  typical  of  the  entire  class.  It  commences  in  the  interstices  of  the 
parenchyma,  with  peculiar  ciliated  infundibuli  which  will  be  described 
further,  the  capillary  processes  of  which  go  on  uniting  into  larger  branches, 
and  finally  form  two  large  collecting  vessels,  which,  sometimes  separately  and 
sometimes  united,  open  to  the  exterior  through  one,  two,  or  numerous  pores. 

Nearly  all  the  Platyhelminthes  are  HERMAPHRODITIC  [the  exceptions  are  the 
Bilharzia,  Micvostomidce  and  Nemertinea — F.  V.  T.],  and  in  nearly  all  there 
are  in  addition  to  the  ovaries  producing  ova,  other  glands  attached  to  the 
female  genital  apparatus,  namely,  the  yolk  glands,  which  provide  a  sub- 
stance termed  yolk,  which  serves  as  nourishment  for  the  embryo.  The 
fully-formed  eggs  have  shells  and  are  composed  of  the  ovum,  which  is 
surrounded  by  numerous  yolk  cells  or  their  product  of  disintegration.  The 
two  sexual  openings  usually  lie  close  together,  frequently  in  the  base  of  a 
genital  atrium  ;  they  are  rarely  separated  from  one  another.  Shell-glands 
also  usually  occur. 

Reproduction  is  sexual,  often,  however,  combined  with  asexual  methods 
of  propagation  (segmentation,  budding).  The  Platyhelminthes  live  partly  free 
in  fresh  or  salt  water,  exceptionally,  also,  on  land.  The  greater  part, 
however,  live  as  parasites  on  or  in  animals. 


CLASSIFICATION  OF  THE  PLATYHELMINTHES. 

Class  I. — Turbellaria,  or  Eddy  worms.  Flat  worms  for  the  most  part, 
free-living  and  always  covered  with  a  ciliated  epithelium.  [They  are 
usually  leaf-shaped  or  oval.— F.  V.  T.]  Their  intestine  is  either  simple 
(JRhabdoccBlida)  or  ramified  (Dendroccelidd},1  or  they  have  an  entodermal  syn- 
cytium  gradually  dispersed  throughout  the  parenchyma  {Acceld}?  Develop- 
ment direct  or  through  metamorphosis.  They  live  in  fresh  and  salt  water 
or  on  land  ;  very  seldom  as  parasites. 

Class  II. — Trematoda,  Sucking  worms.3  [Usually  known  as  Flukes. — 
F.  V.  T.]  Flat  worms,  living  as  ecto-  or  endoparasites,  that  are  only 

1  [These  are  also  known  as  Polycladida  and  Tricladida. — F.  V.  T.] 

2  [These  are  a  division  of  the  Rhabdocalida. — F.  V.  T.] 

3  This  grouping  goes  back  to  the  year  1800,  and  was  made  by  J.  G.  H.  Zeder, 
a  doctor  and  helminthologist  of  Forchheim,  who  divided  the   helminths,  which  until 
1851  were  generally  regarded  as  particular    classes  of    animals,   into    the    groups  of 
hook,  round,  sucker,  tape  and  cyst  worms,  as  which  they  are  recognised  up  to  the 
present  time.  -  In  1809,  however,  K.  A.  Rudolphi  gave    them  the  names,    Nematodes, 
Acanthocephali,  Trematodes,  Cestodes  and  Cystici. 


TREMATODA  I2Q 

ciliated  in  the  larval  condition,1  and  in  their  adult  state  are  covered  with 
a  cuticle,  the  matrix  cells  of  which  are  sunk  into  the  parenchyma.  They 
have  either  one,  a  few,  or  several  sucking  discs,  and  frequently  also  possess 
chitinous  clasping  [suckers  with  chitinous  armour]  and  clinging  organs  [hooks]. 
The  intestine  is  simple,  but  generally  bifurcated,  and  not  rarely  there  are  trans- 
verse anastomoses  between,  or  blind  ducts  at  the  branches  of,  the  fork. 
Excretory  organs  double,  with  two  orifices  at  the  anterior  extremity  or  a  simple 
one  at  the  posterior  end.  [The  two  trunks  usually  open  into  a  common 
contractile  vesicle,  which  opens  at  the  posterior  end  of  the  body. — F.  V.  T.] 
Development  takes  place  by  a  metamorphosis  or  alternation  of  generations. 
These  worms  are  almost  always  hermaphroditic;  with  two  [Polytomum  and 
most  Monogenea]  or  several  female  and  one  male  sexual  orifices.-  They  live, 
almost  without  exception,  as  parasites  on  vertebrate  animals,  but  the  inter- 
mediatry  generations  are  passed  in  molluscs, 

Class  III. — Cestoda  (Tape  worms).  Endoparasitic  flat  worms  without  an 
alimentary  canal.  The  larval  stages  are  rarely  ciliated,  but  are  usually  provided 
with  six  hooklets  ;  the  adult  worm  is  covered  with  a  cuticle,  the  matrix 
cells  of  which  are  sunk  into  the  parenchyma.  The  body  is  either  simple 
(Cestodaria),  or  composed  of  a  chain  of  segments,  in  which  case  it  consists  of  the 
scolex,  and  the  segments  containing  the  sexual  organs  '(Proglot tides)  (Cestodes 
s.  str.).  The  scolex  is  provided  with  various  sucking  and  clinging  organs,  and 
there  are  calcareous  bodies  in  the  parenchyma.  Excretory  organs  symmetrical, 
opening  at  the  posterior  end.  These  worms  are  almost  always  hermaphroditic, 
and  trien  possess  one  or  two  female  and  one  male  sexual  orifice.  During 
development  a  larval  intermediary  stage  termed  "  cysticercus  "  appears 
which  almost  always  lives  as  the  sexual  animal  in  another  host.  The 
adult  stage  is  parasitic  in  vertebrate  animals  and  the  larval  stage  in 
invertebrates.  [This  is  not  always  the  rule,  for  this  cyst  stage  occurs 
abundantly  in  vertebrates,  such  as  Cysticercus  celluloses  in  the  pig,  Cysti- 
cercus pisciformis  in  rabbits,  &c. — F.  V.  T.] 


Class  I.     T*ematoda,   Rud. 

These  worms  are  usually  leaf-  or  tongue-  shaped,  rarely  barrel- 
shaped  or  conical  ;  they  vary  from  0*1  mm.  to  almost  i  m^^Tn 
length;  most  of  them,  however,  are  small  (5  —  15  mm.).  The  sur- 
face on  which  the  orifice  of  the  uterus  and  the  male  sexual 
opening  are  situated  is  termed  the  ventral  surface  ;  the  oral 
aperture,  which  also  acts  as  anus,  is  always  at  the  anterior  end,. 
except  in  the  genus  Gasterostomum,  which  is  parasitic  in  fishes. 

Sucking  discs  are  common  and  occur  in  varying  numbers  and 
positions  at  the  anterior  and  posterior  extremities  as  well  as  on  the 
ventral  surface,  and  occasionally  on  the  lateral  border  and  on  the 


1  [An  exception  to  this  occurs  in  Temnocephala,  in  which  the  skin,  especially  on  the 
surface  of  the  tentacles,  is  provided  here  and  there  with  cilia.  —  F.  V.  T.] 

2  [In  Diplozoon  and  one  or  two  other  forms  the  vagina  is  unpaired.  —  F.  V.  T.] 

9 


130  THE    ANIMAL    PARASITES    OF    MAN 

dorsum  ;  usually  also  the  beginning  of  the  intestine  is  surrounded 
by   a   sucker. 

Tn  or  near  the  suctorial  apparatus  there  are  chitinous  hooks, 
claws  or  claspers,  or  the  surface  of  the  body  is  more  or  less 
covered  with  spines,  scales  or  prickles  ;  in  one  species  (Rhop alias) 
there  is  a  projectile  rostrum  beset  with  spines. 

The  body  of  all  the  Trematodes  is  covered  by  a  homogenous 
CUTICLE  of  varying  thickness,  which  either  lies  directly  over  the 
external  layer  of  the  p'arenchyma,  which  is  thickened  into  a  kind 
of  basement  membrane,  or  is  situated  immediately  over  the 
muscles  embedded  in  the  parenchyma.  The  pyriform  or  fusiform 
EPITHELIAL  CELLS  lie  in  groups  with  their  thickest  parts  between 
or  directed  towards  the  internal  of  the  diagonal  muscles,  but  a 
process  directed  outwards  also  connects  them  with  the  basal 
surface  of  the  cuticle.  There  are  also  unicellular  cuticular  glands, 
lying  isolated  or  in  groups,  which  are  termed  head,  abdominal,  or 
dorsal  glands  according  to  the  position  of  their  orifice. 

.THE  PARENCHYMA  is  a  connective  substance,  i.e.,  it  consists  of 
numerous  multipolar  cells,  the  offshoots  from  which  branch  strongly, 
then  anastomose  with  each  other  as  well  as  with  the  offshoots  of 
other  cells,  so  that  a  network,  permeating  the  entire  body  and 
encompassing  all  the  organs,  is  produced.  There  is  in  addition  a 
homogenous  matrix,  in  the  form  of  lamellae  and  trabeculae,  that 
border  small  cavities  communicating  with  each  other  and  filled  with 
a  liquid  substance.1  In  some  species  the  parenchyma  encloses 
pigment  cells. 

The  MUSCULAR  SYSTEM  of  the  Trematodes  is  composed  of  a 
musculo-dermal  tube,  the  dorso- ventral  or  parenchj/mal  muscles,  the 
suctorial  discs,  and  the  special  muscles  of  certain  organs. 

The  musculo-dermal  tube,  which  lies  fairly  close  to  the  cuticle, 
consists  of  annular,  transverse,  and  longitudinal  fibres  which 
surround  the  entire  body  in  one  or  several  layers,  and  as  a  rule 
are  more  strongly  developed  on  the  ventral  surface  as  well  as  in  the 
anterior  part  of  the  body.  The  MUSCLES  OF  THE  PARENCHYMA  are 
found  chiefly  in  the  lateral  parts  of  the  body  and  pass  through 


1  According  to  other  authors,  the  parenchyma  of  the  Trematodes  consists  originally 
of  similar  cells,  of  which,  however,  in  the  adult  stage,  only  the  cellular  membranes 
have  remained,  between  which  an  intercellular  mass  has  appeared,  while  the  proto- 
plasm has  been  transformed  into  a  watery  liquid  in  which  only  here  and  there  a  nucleus, 
surrounded  by  a  little  unaltered  protoplasm,  has  remained.  By  partial  absorption 
of  the  walls  contiguous  spaces  become  connected,  and  their  originally  flat  partitions 
become  trabeculae. 


TREMATODA 


Ut. 


Oat. 


tr  c.v. 


the  parenchyma  in  a  dorso-ventral  direction  ;   their  diverging  brush- 
like  ends  are  inserted  on  the  inner  surface  of  the  cuticle  (fig.  67). 

The  suctorial  discs  seem  to 
be  specially  differentiated  parts 
of  the  musculo  -  dermal  tube. 
Their  concave  inner  surface  is 
lined  by  the  continuation  of  the 
cuticle  and  their  vaulted  ex- 
ternal surface  is  covered  by  a 
more  dense  tissue  that  frequently 
takes  the  form  of  a  shiny  mem- 
brane. 

The  principal  mass  of  the 
suctorial  discs  consists  of  mus- 
cular fibres  which  run  in  three 
directions  —  equatorial,  meridi- 
onal and  radial.  The  equa- 
torial fibres  correspond  to  the 
annular  muscles,  the  meridional 
fibres  to  the  longitudinal  mus-  v  de 
cles,  and  the  radial  fibres  to  the 
muscles  of  the  parenchyma ;  the 
radial  fibres  are  always  most 
strongly  developed.  The  func- 
tion of  these  muscles  is  con- 
sistent with  their  position  ;  the 


meridional     fibres     flatten      the 

suctorial  disc    and    diminish   the 

depth  of  its  cavity,  so  that  the 

internal    surface   may  touch    the 

object  to  be   held  ;   if  the  equa-  h. 

torial   fibres    then    contract,    the  FIG.   66.  —  Polystomum    integerrimum 

•   i                             ,                            f  from   the    urinary    bladder   of    the    frog. 

suctorial   pore  rises  by  means   of  (After  Zellen)     ^  intestine;    h.,  large 

longitudinal    stretching,   and    the  hook  of  the  sucker  '•   hk->  smaiier  hook- 

,                            .  lets  ;    Lc.v.,    longitudinal    canals    of    the 

inner     Slirlace    Ol      the      organ     IS  vitelline  sac;  o.,  oral  orifice  ;  oot.,  ootype  ; 

drawn  in   by  the   contraction   of  °°-  ovary ;   S-P-  suctorial  Pores  <>*  the 

J  disc  ;  tr.c.v.,   transverse  canals  of  the  vi- 

the     radial     muscles.        Thus     the  telline  sac  •   «/.,  uterus  with  ova  ;  v.,  en- 

sucking  disc    becomes   adherent.  ^du^S;  tatMLFSTE 

Usually  also    there  is    a    Sphincter  telline  sac  and   testicular  vesicles  are  not 

at    the    border   of    the    suckers,  seen'    (Magnified-> 

which   plays   its   part  during  the  act    of  adhesion    by    constricting 

in    a  circular  manner  that  part  of  the  mucous  membrane  to  which 


s.p 


132 


THE    ANIMAL    PARASITES   OF    MAN 


it  is  attached.  The  loosening  of  the  fixed  sucker  is  effected  by 
relaxation  chiefly  of  the  radial  fibres,  by  the  contraction  of  the 
meridional  fibres  and  certain  bundles  of  muscles  situated  at  the 
base  and  in  the  periphery  of  the  suckers.  The  connective  and 
elastic  tissues  between  the  muscles  of  the  suckers  probably  also 
take  part  in  this  process. 

Of  the  muscles  of  the  organs  which  have  developed  from  the 
parenchyma  muscles  we  may  briefly  mention  those  bundles  that  are 
attached  to  certain  parts  of  the  genital  apparatus,  to  the  suckers, 
to  the  hooks  and  claws,  and  also,  at  all  events  in  Distomum 
hepaticum,  to  the  spines.  The  sheaths  used  for  the  projection  of 
the  rostrum  of  the  Rhopaliadea  are  also  muscular. 


T. 


F.-v.s 


Md. 


Ex.v. 


FIG.  67. — Half  of  a  transverse  section  through  Fasciola  hepatica,  L.  25/1.  Cu., 
Cuticle  with  scales;  under  the  cuticle  are  circular  muscles  which  adjoin  the  longitu- 
dinal and  diagonal  muscles ;  within  the  latter  are  the  matrix  cells  of  the  cuticle  ; 
/.,  intestinal  tube  ;  .the  remaining  similarly  contoured  space  cavities  are  intestinal 
culs-de-sac  that  have  been  transversely  or  obliquely  sectioned  ;  F.v.s.,  follicles  of 
the  vitelline  sac  ;  Ex.v.,  excretory  vessels  ;  T.,  testicular  tubules  ;  Md.,  median 
plane  ;  the  fibres  passing  from  the  ventral  to  the  dorsal  surface  are  the  muscles  of 
the  parenchyma.  The  parenchyma  itself  is  omitted. 

The  contractile  elements  consist  of  fibres  of  various  lengths 
that  are  mostly  parallel  to  one  another,  and  frequently  anasto- 
mose ;  a  cortical  substance  of  delicate  fibres  can  usually  be  dis- 
tinguished from  an  internal  homogenous  mass  ;  large  nucleated 
cells  of  equal  size  are  always  connected  therewith,  these  have 
been  variously  named,  but  have  finally  proved  to  be  myoblasts ; 
one  or  more  of  their  processes  are  the  muscular  fibres. 

The  MOVEMENTS  of  the  Trematodes  consist  in  alterations  of 
form  and  position  of  the  body,  as  well  as  in  creeping  movements. 


TREMATODA 


133 


O.s 


N.ph. 


M.I. 


In  the  NERVOUS  SYSTEM  (fig.  68)  can  be  distinguished  a  cerebral 
portion  as  well  as  fasciculi  (usually  termed  nerves)  running  from 
them,  and  peripheral  nerves.  The  cerebral  portion  always  consists 
of  two  large  ganglia  situated  in  the  anterior  end  of  the  body 
which  pass  dorsally  over  the  oesophagus  and  are  connected  by 
means  of  a  broad  and 
thick  commissure  com- 
posed of  fibres  only. 
From  each  ganglion  three 
nerves  project  towards 
the  front — the  inner  and 
dorsal  nerve  for  supply- 
ing the  anterior  dorsal 
part  of  the  body ;  the 
median  and  ventral  for 
the  oral  sucker  :  and  the 
exterior  and  lateral  like- 
wise for  the  supply  of  the 
sucker. 

In  a  similar  manner 
three  fasciculi  proceed 
backwards  from  each 
ganglion,  one  dorsal,  one 
lateral  and  one  ventral. 
The  dorsal  and  ventral 
fasciculi  become  united 
and  curve  backwards  ; 
the  symmetrical  lateral 
fasciculi  are  connected  by 
means  of  transverse  com- 


G.p. 


E.xp. 


FIG.  68. — Harmostomum  leptostomum  (Olss.) 
in  its  immature  condition  (from  Helix  hortensis}. 
missures,  the  number  Ot  Nervous  system,  according  to  Bettendorf,  mag- 
™;V»irTi  varv  irrorrHnp-  to  nified  :  A's"  Abdominal  sucker;  C.g.,  cerebral 
Which  \ary  aCC  ganglion;  Ex.p.,  excretory  pore;  G.p.,  genital 

the     species.        Such     com-        pore  ;  O.s.,  oral  sucker  ;    M.d.,  dorsal  medullary 
-,  v  fasciculus  ;    M.I.,    lateral    medullary    fasciculus ; 

missures    also    exist  N^  pharyngeal  nerve .  MmVtt  ventrai  medui- 

tween  the  lateral  and  the      lary  fasciculus. 
two  other  fasciculi  on  each 

side.  There  are  ganglion  cells  along  the  entire  course  of  the  pos- 
terior cords,  more  particularly  at  the  points  of  departure  of  the 
commissures.  There  also  appears  to  be  in  addition  a  fourth  an- 
terior and  posterior  pair  of  nerves,  the  front  pair  for  the  oral 
sucker  and  the  hind  pair  for  the  pharynx. 

The    peripheral   nerves,   which   spring   from    the  %  posterior   cords 


134 


THE   ANIMAL  PARASITES  OF   MAN 


as  well  as  from  the  commissures,  either  pass  directly  to  the  mus- 
cular fibres  or  to  the  sensory  cells  that  are  situated  at  about  the 
same  level  as  the  sub-cuticular  cells,  or  they  reach  these  after  the 
formation  of  a  plexus  situated  immediately  beneath  the  fibres  of 
the  cuticular  muscles  ;  the  processes  directed  outwards  terminate 
in  small  vesicles  in  the  cuticle. 

As   to   other   ORGANS   OF   SENSE,    simple   eyes,    two   or   four   in 
number,   are   known   in  several  ectoparasitic   species  as   well   as   in 

a  few  free-living  larval  stages  of  endo- 
parasitic  forms  (Cercaria).  In  the 
adult  stage,  however,  they  usually 
undergo  complete  retrogression. 

The        ALIMENTARY      CANAL        COm- 

mences  with* an  oral  aperture  situated 
on  the  ventral  surface  of  the  anterior 
extremity  and  usually  connected  with 
an  oral  cavity  surrounded  by  a  sucker ; 
the  oesophagus  of  varied  length  is  di- 
rected backwards  and  is  generally 
provided  with  an  elastic  muscular 
pharynx  (fig.  69).  Sooner  or  later 
the  intestine  divides  into  two  lateral 
branches  directed  backwards,  both  of 
which  end  blindly  at  the  same  level.1 
In  many  ectoparasites  (Monogenea) 
a  connection  is  established  between 
the  genital  glands  and  one  of  the  intes- 
tinal branches  [ductus  vitello-intestinalis  (fig.  66).]  [This  duct  has 

1  The  following  conditions  represent  deviations  from  this  type  :  ( i )  In  Gastero- 
stomum  the  oral  aperture  is  situated  in  the  middle  of  the  ventral  surface,  and  occasion- 
ally is  even  nearer  to  the  posterior  than  to  the  anterior  end.  There  is  no  proper  oral 
sucker,  but  the  pharynx  is  thus  termed.  (2)  A  few  genera,  such  as  Gasterostomum, 
Aspidogaster,-  Diplozoon,  &c.,  have  only  one  intestinal  pouch,  which  is  undoubtedly 
to  be  understood  as  representing  the  primitive  condition,  as  it  is  also  often  found  in 
the  young  stages  of  the  Trematodes.  (3)  The  branches  of  the  intestines  are  curved  and 
united,  behind  (several  Tristomidea  and  Monostomidea),  while  in  Polystomum  integerri- 
mum  (in  the  bladder  of  frogs)  there  are  several  commissures  between  the  intestinal 
branches,  and  in  Schistosominea  the  united  intestinal  branches  proceed  as  one  channel 
towards  the  posterior  end.  (4)  The  termination  of  the,  two  intestinal  branches  is  not 
always  on  a  level,  they  are  therefore  of  different  lengths.  (5)  When  the  oesophagus 
is  very  long  the  intestinal  branches  extend  both  forward  and  backward,  so  that  the  gut 
exhibits  the  form  of  an  H.  (6)  In  the  broad  and  flat  species  the  intestinal  diverticules 
mostly  develop  laterally,  or  may  also  run  along  the  median  line,  and  may  again  branch 
off.  (7)  In  a  few  cases  (Nematobothrium,  Didymozoon)  the  intestine  completely  dis- 
appears up  to  the  pharynx. 


FIG.  69.  Median  section  through 
the  anterior  part  of  Distomum 
hepaticum  ;  the  oral  sucker, 
pharynx  with  bursa  and  the  oeso- 
phagus have  been  cut  through. 


TREMATODA 


135 


apparently  the  same  relations  as  the  "  canal  of  Laurer "  of  the 
Digenea,  except  that  the  latter  opens  to  the  exterior  direct.— 
F.  V.  T.]. 

The  oral  cavity,  the  oesophagus,  and  the  pharynx  with  its  pharyn- 
geal  bursa,  are  lined  with  a  continuation  of 
the  cuticle  of  the  body ;  the  .  intestinal 
branches  are  lined  with  high  cylindrical 
epithelium  (fig.  67).  The  oesophagus  and 
intestinal  branches  also  have  often  one 
layer  of  annular  and  longitudinal  mus- 
cles ;  the  pharynx  has  essentially  the  struc- 
ture of  a  sucker  (fig.  69). 

The  accessory  organs  of  the  alimentary 
canal  consist  of  groups  of  unicellular  SALI- 
VARY GLANDS  that  discharge  into  the 
oesophagus  in  front  of  or  behind  the 
pharynx,  or  even  into  the  pharynx  itself. 

The  food  of  the  Trematodes  consists 
of  cutaneous  mucous,  epithelial  cells,  the 
intestinal  contents  of  the  hosts,  and  often 
also  of  blood,  and  this  not  only  in  those 
species  living  in  the  vascular  system,  or  in 
the  intestine  or  biliary  passages  of  their 
hosts,  but  also  in  species  living  as  ectopara- 
sites. 

The  final  products  of  assimilation  which 
are  soluble  in  the  fluids  of  the  body  are 
distributed  throughout  the  parenchyma 
and  are  thence  expelled  by  a  definite 
tubular  system  (excretory  apparatus,  proto- 
nephridia,  formerly  also  termed  the  water- 
vascular  system).  This  system,  which  is  FlG>  ;o-  _  AUocreadium 
distributed  throughout  the  entire  body  isoporum  (Looss).  38/1.  Ex- 

.„  .  ,-      11        i         i          i  i        cretory   apparatus.       Of   the 

(fig.  70)  IS  Symmetrically  developed,  and,  other  organs,  the  oral  sucker, 
in  the  mOHOgenetic  (ectoparasitic)  Tre-  Pharynx,  genital  pore,  ab- 


dominal sucker,  ovarium  and 
testes  are  sketched  in  ;  the 
cylindrical  excretory  bladder 
is  in  the  posterior  end.  (After 


matodes   it   opens,   right   and   left,    at   the 

anterior  end  of  the  dorsal  surface  ;  in  all 

other  species,   however,  it  opens  singly  into     Looss.) 

the   excretory  pore    (foramen   caudale)    at 

the  centre  of  the  posterior  border  ;   in  those  cases,  however,  where 

a  sucker  is   present    at    the    posterior   end,   as    in    the    Paramphis- 

tomidea,  the  excretory  pore  is  situated  on  the  dorsal  surface  close  in 

front  of  the  sucker. 


136 


THE    ANIMAL    PARASITES    OF    MAN 


The  EXCRETORY  SYSTEM1  consists  of  several  parts  :  (i)  of  the 
more  or  less  numerous  terminal  or  infundibular  cells  (figs.  70,  71) ; 
(2)  of  the  capillaries  joined  to  them  ;  (3)  of  larger  vessels  taking  up 
the  capillaries,  and  (4)  of  the  excretory  bladder.  Terminal  cells  and 
capillaries  may  be  compared  to  unicellular  glands  with  long  excretory 
ducts  ;  the  cellular  body  (fig.  71)  is  comparatively  large,  stretched 
lengthways,  more  rarely  transversely,  and  provided  with  numerous 

processes  that  are  lost  in  the  parenchyma  ; 
it  contains  within  a  conical  alveolus  (analogous 
with  the  secretory  space  of  unicellular  glands) 
which  continues  direct  into  the  structureless 
capillary  ;  at  its  blind  end  is  a  bunch  of  cilia 
which  reaches  the  open  space,  and  which, 
during  life,  shows  a  waving  motion  (ciliary 
movement).  In  the  protoplasm  of  the  ter- 
minal cell  at  its  blind  end  the  nucleus  is 
situated. 

The  entire  apparatus  begins  as  a  cul-de- 
sac,  i.e.,  enclosed  within  the  terminal  cells, 
to  which  may  be  ascribed  the  capacity  of 
taking  up  from  the  fluid  that  permeates 

the  parenchyma  the  part  to  be  excreted,  which  is  first  collected 
into  their  own  cavities  and  thence  carried  out  by  means  of  the 
capillaries  and  vessels. 

The  vessels  possess  definite  walls,  but  some  authors  state  that 
these  canal-like  spaces  taking  up  the  capillaries  are  only  separated 
by  a  homogenous  layer  belonging  to  the  parenchyma.  They  may 
repeatedly  reunite  on  either  side,  and  again  give  rise  to  other  canals 
(GATHERING  TUBES),  which  finally,  travelling  towards  the  posterior 
end,  discharge  into  the  excretory  bladder  (fig.  70). 

The  form  and  size  of  the  bladder  varies  much  according  to  the 
different  species,  but  it  always  possesses  its  own  epithelium,  sur- 
rounded by  circular  and  longitudinal  muscles,  the  circular  muscles 
forming  a  sphincter  around  the  opening.  Frequently  also  the 
structure  of  the  bladder  extends  to  the  tubules  discharging  into 
it,  which  therefore  are  not  to  be  regarded  as  separate  "  vessels," 
but  rather  as  tubular  diverticula  of  the  bladder,  directed  anteriorly. 
In  some  few  species  the  diverticula  also  branch  off  -and  the 
branches  anastomose,  so  that  a  network  of  tubules  ensues  which 


FIG.  71. — Terminal  cells 
of  Cotylogonimus  hetero- 
phyes  (v.  Sieb.)-  700/1. 
Left  from  the  side,  right 
from  the  surface.  (After 
Looss.) 


1  The  following  description  relates  to  the  Fasciolidea. 


TREMATODA 


137 


is  connected  with  the  vessels.  In  such  cases  there  are  also  ciliary 
lobes  in  the  tubules. 

The  contents  of  the  entire  apparatus  usually  consist  of  a  clear 
or  sometimes  reddish  fluid  ;  in  some  species  there  are  larger  or 
smaller  granules,  and  occasionally  concretions  also  occur. 

Sexual  Organs. — Nearly  all  the  Trematodes  are  hermaphrodites, 
and  only  a  few  (Schistosominea,  Koellikeria)  are  sexually  differen- 


y.d. 


FIG.  72. — Opisthioglyphe  endo- 
loba  (Duj.),  from  the  frog.  Male 
genitals.  71/1.  A.s.,  abdom- 
inal sucker;  C.p.,  cirrus  pouch, 
with  cirrus,  prostatatic  cells 
and  vesicula  seminalis  ;  G.p., 
genital  pore  ;  T.,  testes  ;  Ut., 
terminal  portion  of  the  uterus  ; 
V.d.,  vas  deferens.  (After 
Looss.) 


V.S.: 


FIG.  73. — Opisthioglypbe  endoloba  (Duj.).  Female 
genitals.  71/1.  A.,  Abdominal  sucker  ;  C.,  pouch 
of  cirrus  ;  V.d. ,  vitelline  duct  ;  V.s.,  vitelline  sac  ; 
L.C.,  Laurer's  canal  ;  7?.s.,  receptaculum  seminis  ; 
U.,  uterus  ;  K.,  ovary.  (After  Looss.) 


tiated.  The  sexual  organs  usually  lie  in  the  "  central  field " 
surrounded  by  the  intestinal  branches  ;  the  vitelline  sacs,  on  the 
other  hand,  are,  as  a  rule,  placed  laterally  beyond  the  intestinal 
branches  in  the  lateral  areas. 

The  male  apparatus1  is  composed  of  two  variously  formed 
testes  (fig.  72)  (globular,  oval,  indented,  lobulated,  or  ramified) 
which  may  lie  side  by  side  or  one  behind  the  other,  from 
each  testicle  a  tube  (vas  efferens)  originates  ;  sooner  or  later,  both 
tubes  become  as  a  rule  united  to  form  the  muscular  vas  deferens 


1  The  following  description  mostly  relates  to  the  Fasciolidea. 


138  THE  ANIMAL  PARASITES  OF  MAN 

which  opens  close  to  the  genital  orifice,  or  more  rarely  discharges 
direct  into  the  genital  pore  and  enters  the  muscular  CIRRUS 
POUCH  ;  the  cirrus  itself,  after  being  exerted,  may  be  projected, 
and  serves  as  an  organ  of  copulation.  In  the  atrium,  and  as  a 
rule  enclosed  in  the  cirrus  pouch,  is  found  a  mass  of  one-celled 
glands  (prostata)  as  well  as  a  vesicula  seminalis  (which  is  likewise 
within,  or  may  also  be  outside  the  pouch). 

The  female  genitals  (fig.  73)  consist  of  an  ovary  usually  situated 
in  front  of  the  testes,  the  form  of  which  varies  according  to  the 
species,  the  usual  pair  of  vitelline  sacs,  the  conducting  passages  and 
a  number  of  auxiliary  organs  ;  the  short  oviduct  directed  towards 
the  centre  starts  from  the  ovarium,  and  is  connected  at  the 
median  line  with  the  excretory  ducts  of  the  vitelline  glands.  These 
grape-like  glands  possess  longitudinal  excretory  ducts,  which  assume 
an  oblique  direction  behind  the  ovary,  unite  together  at  the  median 
line  and  form  one  single  tube,  often  carrying  a  vitelline  reservoir 
that  unites  with  the  oviduct.  At  this  spot,  moreover,  there 
frequently  occurs  a  canal  (Laurer's  canal)  which  originates  on  the 
dorsal  surface,  and  to  the  inner  end  of  which  a  vesicle  filled 
with  sperm  (receptaculum  seminis)  is  usually  suspended.  More- 
over, there  are  also  numerous  radial  one-celled  glands  (shell  glands) 
at  the  place  where  the  oviducts,  vitelloducts  and  Laurer's  canal 
are  united.  In  this  region  (ootype),  which  is  usually  distended, 
the  germ  cells  are  fertilised,  surrounded  with  vitellus  and  shell 
material,  and  as  ova  with  shells  they  pass  direct  to  the  uterus, 
which,  with  its  many  convolutions,  occupies  a  larger  or  smaller 
portion  of  the  central  field,  but  the  terminal  part  of  which  lies 
next  the  cirrus  pouch  and  discharges  beside  the  male  orifice  either 
to  the  surface  of  the  body  or  into  a  genital  atrium.  The  terminal 
portion  of  the  uterus,  which  is  often  of  a  particular  formation, 
serves  as  a  vulva  (METRATERM). 

The  orifice  of  the  sexual  organs  is  generally  situated  at  or 
near  to  the  median  line  on  the  ventral  surface  and  in  the  anterior 
region  of  the  body  ;  in  the  Fasciolidea  it  is  frequently  in  front  of 
the  ventral  sucker,  in  other  families  at  a  suitable  spot  in  the 
vicinity  of  the  intestinal  bifurcation.1 


1  The  typical  position  of  the  genitals  is  subject  to  many  deviations,  which  are  of 
importance  in  the  differentiation  of  the  species  and  families.  The  following  lines 
give  some  few  of  these  deviations  :  ( i )  The  genital  pore  remains  on  the  ventral  sur- 
face, but  is  situated  next  to  or  behind  the  abdominal  sucker,  or  it  becomes  marginal, 
and  is  then  found  in  front  of  or  next  to  the  oral  sucker  or  at  a  lateral  edge,  or, 
finally,  in  the  centre  of  the  posterior  border ;  the  conducting  passages  also 


TREMATODES I    DEVELOPMENT  139 

The  spermatozoa  do  not  differ  essentially  in  their  structure 
from  those  of  other  animals  ;  the  germinal  cells  or  ova  are  cells 
without  integument  and  which  contain  a  large  nucleus  and  a 
little  protoplasm  ;  the  vitelline  sacs  also  yield  nucleated  cells,  in 
the  plasm  of  which  there  are  numerous  yellow  yolk  granules  ;  the 
yolk  cells,  like  the  germinal  cells,  detach  themselves  from  the 
ovarium  and  move  into  the  excretory  ducts  to  surround  each 
germinal  cell  in  the  ootype.  They  disintegrate  sooner  or  later, 
in  the  complete  ovum,  and  there  are  utilised  as  food  by  the 
developing  embryo. 

DEVELOPMENT  OF  THE  TREMATODES, 

(1)  Copulation. — Observation   has  demonstrated   that  the  one  or 
two  vaginae  occurring  in  the  ectoparasitic  Trematodes   are  utilised 
as  female   organs   of  copulation,   and  that   the  -copulation  is  alter- 
native ;  it  is  also  known  that  Laurer's  canal,  which  was  formerly 
generally  indicated   as   the   vagina,   has   never  served   the  digenetic 
Trematodes    as    such  —  it    appears    to     be    homologous    with    the 
canalis  vitello  intestinalis   of   the   Monogenea — but   is   the   terminal 
portion   of    the    uterus   termed   metraterm.      Reciprocal   copulation 
is   observed  as   well  as  auto-copulation  and  auto-fecundation.     The 
spermatozoa    accordingly    wander    through    the    entire    uterus    till 
they  reach  the  place  of  their  final  abode. 

(2)  Formation    of    the    Ova. — The    germinal    cells    are    probably 
already  fertilised  in   the  germinal  ducts  and  then  pass  singly  into 
the  space  where   they  develop  and  where  a  large   number  of   yolk 
cells  collect  around  them  (fig.  74).     The  shell  is  then  formed  from 
the  secretion  of    the   shell  glands,  which  exudes  in  drops,  the  wall 
of  the   oot}Tpe   meanwhile  contracting  considerably,   and   the  ovum 
moving  into  the  uterus.     The  completed  ova  are  of  various  forms 


correspondingly  alter  their  direction.  (2)  The  germinal  trunk  usually  lies  in  front 
of  the  testes,  not  rarely,  however,  behind  them  or  between  them.  (3)  The  three 
genital  glands  mostly  lie  together  close  in  front  of,  or  behind,  the  centre  of  the  body  ; 
they  may  be  moved  far  back,  and  may  incidentally  become  separated  one  from  the 
other.  (4)  The  vitelline  sac  may  be  single,  in  which  case  it  also  then  lies  in  the  central 
field.  (5)  A  few  forms  possess  but  one,  others  several  or  numerous  testes.  Amongst 
the  ecto-parasitic  Trematodes  there  are  also  varieties  with  but  one  testis  ;  but  they 
mostly  have  several.  As  a  rule,  their  uterus  is  short"  but  the  ootype  well  developed. 
The  particular  single  or  double  canals  (vagina)  are  used  for  copulation,  not  the  uterus. 
The  vitelline  ducts  also  communicate  with  the  intestine  through  the  canalis  vitello- 
intestinalis. 


140 


THE  ANIMAL  PARASITES  OF  MAN 


and  sizes.  They  are  mostly  oval,  at  all  events  in  the  digenetic 
Trematodes,  and  the  yellowish  or  brown  shell  is  provided  with  an 
opening  at  one  pole  which  is  closed  up  by  a  watch-glass-shaped 
cover.  Appendices  (filaments)  on  the  shell — at  one  or  both  poles 
— are  uncommon,  but  are  the  rule  in  the  ova  of  the  Monogenea. 
The  latter  contain  very  few  or  only  one  ovum  in  their  uterus, 
whereas  in  the  Digeriea  the  number  of  ova  is  large,  often  even 
very  considerable  ;  correspondingly  the  ova  are  also  very  much 
smaller. 

(3)  Deposition  of  the  Ova.  —  Soon  after  the  formation  of  the  ova 
the  Monogenea  deposit  them  round  the  place  of  their  attachment  on 


FIG.  74. — Ovum  of  Fasciola 
hepatica  (L.),  cut  longitudi- 
nally. The  cover  has  been 
removed  in  the  process. 
Within  the  shell  numerous 
yolk  cells,  and  at  the  lid  end 
there  is  the  still  unsegmented 
ovum  (dark).  240/1. 


FIG.  75. —  Miracidium  of 
Distomum  hepaticum  that  has 
just  hatched  from  the  egg, 
and  has  a  distinct  cuticular 
epithelium  (magnified). 
(From  Leuckart.) 


the  skin  or  the  gills  of  their  hosts.  The  embryonic  development 
thus  takes  place  outside  the  parent ;  in  other  Trematodes  the  ova 
remain  in  the  uterus  for  a  longer  or  shorter  period,  and  in  it  often 
go  through  the  entire  development  or  a  part  of  it.  Sooner  or 
later  the  ova  are  deposited  and  leave  the  affected  organs  by  the 
natural  channels. 

(4)  The  embryonic  development,  after  irregular  segmentation, 
leads  to  the  formation  of  a  morula  stage  which  is  surrounded  by 
a  cellular  investing  membrane,  while  the  principal  mass  of  the 
cell  forms  the  embryo,  which  uses  for  its  nourishment  the  yolk 
cells,  which  have  in  the  meantime  disintegrated.  Usually,  after 
the  ova  have  reached  the  water,  the  embryos  hatch  out,  leaving 
their  investing  membrane  in  the  egg-shell ;  in  other  cases,  how- 
ever, the  embryos  only  hatch  out  after  having  been  subjected  to 
the  influence  of  the  intestinal  juices,  that  is  to  say,  in  the  intestine 


TREMATODES  :     DEVELOPMENT  14! 

of  an  intermediary  host  which   has   ingested  with  its  food  the  ova 
escaped  from  the  [primary]  host. 

(5)  The  post-embryonic  development  of  the  Trematodes  is  accom- 
plished in  various  ways  ;  the  process  is  the  most  simple  in  the 
ecto-parasitic  species,  the  young  of  which  are  certainly  to  be 
regarded  as  larvae,  because  they  possess  characteristics  that  are 
lacking  in  the  adult  worms  (cilia,  simple  gut,  &c.),  but  which, 
nevertheless,  pass  into  the  adult  state  direct,  after  a  relatively 
simple  metamorphosis  (Monogenea).  In  the  Holostomidea  that  are 
found  chiefly  in  the  intestine  of  aquatic  birds,  and  which  rarely 
occur  in  other  vertebrates,  the  ova  develop  in  the  water.  The  young 
are  ciliated  all  over,  and,  after  having  entered  an  intermediary 
host  living  in  the  water  (hirudinea,  molluscs,  arthropoda,  amphibia, 
fishes),  they  undergo  a  metamorphosis  into  a  .second  larval  stage  ; 


FIG.  76. — A  group  of  Cercaria  of  Echinostomum  sp.  (from  fresh  water).     25/r. 

they  then  encyst  and  await  transmission  into  the  final  host,  where 
they  become   adult    (metastatic   Trematodes). 

In  the  remaining  so-called  digenetic  trematodes  one  or  two 
intermediate  generations  interpose  between  the  larval  and  ter- 
minal stage,  so  that  quite  a  number  of  adult  animals  may  originate 
from  one  egg.  Usually  the  young,  which  are  termed  MIRACIDIAI 
(fig.  75),  hatch  in  the  water,  where  they  move  with  the  aid  of 
their  cilia.  Sooner  or  later  they  penetrate  into  an  intermediary 
host,  which  is  always  a  snail  or  a  mussel,  and  while  certain  of 
their  organs  disappear,  they  grow  into  an  intestineless  germinal 
body  (sporocyst,  fig.  77).  In  these,  according  to  the  species,  the 


[Also  known  as  ciliated  embryos. — F.  V.  T.] 


142  THE   ANIMAL   PARASITES    OF   MAN 

larval  stages  of  the  forms  that  will  ultimately  become  adult 
(cercaria)  are  produced,  or  the  cercaria  are  only  brought  forth  after 
having  gone  through  another  intermediate  generation,  that  of 
the  REDIAE  (fig.  78),  which  are  always  provided  with  an  intestine. 
The  Cercaria,  as  a  rule,  leave  their  host  and  move  about  in  the  water 
with  the  assistance  of  a  rudder-like  tail  (fig.  76).  After  a  little 
time,  however,  they  usually  again  invade  an  aquatic  animal  (worms, 
molluscs,  arthropoda,  fishes,  amphibians),  then  they  lose  their  tail 
and  become  encysted  ;  here  they  wait  until  they  attain  the  terminal 
host  suitable  for  them,  in  company  with  their  bearer,  and  in  this 
new  situation  they  settle  down  and  reach  maturity.  Or,  again, 
the  cercaria  may  encyst  themselves  in  the  water  or  on  foreign 
bodies  (plants)  and  wait  until  they  are  taken  up  direct  by  the 
terminal  host  [liver 'fluke  of  sheep]. 

Accordingly  the  following  conditions  are  necessary  for  the  com- 
pletion of  the  entire  development  :  (i)  The  terminal  host  in  which 
the  adult  stage  lives  ;  (2)  an  intermediary  host  into  which  the 
miracidia  penetrate  and  in  which  they  become  germinal  tubes  ; 
(3)  a  second  intermediary  host  in  which  the  cercaria  become  en- 
capsuled.  In  certain  species  this  last  stage  is  omitted,  when  their 
cercaria  encyst  themselves,  or,  again  (in  other  species),  it  may  occur 
within  the  first  intermediary  host,  especially  when  the  cercaria 
(which  in  that  case  do  not  acquire  the  oar-like  tail)  do  not 
swarm  out,  but  encyst  themselves  at  once  within  their  sporocysts. 
The  development,  moreover,  may  be  further  complicated  by  rediae 
appearing  in  addition  to  the  sporocysts,  though  this  occurs  in  the 
first  intermediary  host  and  not  in  a  fresh  one. 

Animals  that  harbour  adult  digenetic  Trematodes  have  probably 
become  infected  by  ingesting  their  encysted  forms,  which  they  have 
.either  swallowed  with  certain  animals  (secondary  intermediary 
hosts)  on  which  they  feed,  or  ingested  with  water  or  with  plants, 
or  finally  with  the  first  intermediary  host  ;  whereas  animals  fostering 
encysted  (digenetic)  Trematodes  have  been  infected  by  the  corres- 
ponding cercaria  stages,  and  animals  bearing  germinal  bodies  (sporo- 
.cysts  and  redia),  Have  been  straightway  attacked  by  the  miracidia. 

Certain  species  of  ducks  and  geese  become  infected  with  E chinos- 
tomum  echinatum  by  devouring  certain  water  snails  (Limnceus,  Palu- 
dina)  in  which  the  encysted  stages  occur.  Oxen  become  infected 
with  Paramphistomum  cervi  (i.e.,  Amphistomum  conicum)  by  swallow- 
ing with  the  water,  cysts  of  this  species  which  occur  at  the  bottom 
of  puddles  and  pits.  Sheep  are  infected  with  Fasciola  hepatica  by 
.eating  grass  to  which  the  cysts  of  the  liver  fluke  are  attached  ; 


TREMATODES :  DEVELOPMENT 


143 


our  singing-birds  infect  themselves  or  their  young  with  Urogonimus 
macrostomus  by  tearing  off  pieces  of  the  corresponding  sporocysts 
from  the  snails  (Succinea  amphibia),  which  act  as  the  first  inter- 
mediary hosts,  and  eating,  or  offering  their  fledgelings  these  pieces, 
which  are  full  of  encysted  cercaria. 

The  miracidia  of  the  digenetic  trematodes  are  comparatively 
highly  organised  ;  they  have  a  cuticular  epithelium  (fig.  75)  entirely 
or  partly  covered  with  cilia,  beneath  this  a  dermo-muscular  tube 
composed  of  circular  and  longitudinal  muscles  ;  moreover,  a  simple 
intestinal  sac  with  an  oesophagus,  occasionally  also  with  pharynx, 


FIG.  77. — Development  of  Fasciola  hepatica,  L.  a.,  The  miracidium,  optical  sec- 
tion with  germinal  bodies  and  cilia.  &.,  Young  sporocyst  with  germinal  bodies. 
£..  Sporocysts  with  redia  (magnified).  (From  Leuckart.) 

salivary  glands  and  boring  spine,  also  a  cerebral  ganglion  on  which, 
in  some  species,  there  are  eyes  (fig.  77,  a)  ;  as  to  the  excretory 
organs,  they  are  represented  by  two  symmetrically-placed  terminal 
cells  joined  to  vessels  that  discharge  separately  ;  there  is  a  more 
or  less  ample  (primary)  body  cavity  between  the  parietes  of  the 
body  and  the  intestine  ;  from  the  cellular  parietal  lining  of  this 
cavity  single  cells  become  loosened  (fig.  77,  a,  b),  and  later  become 
cercaria  or  rediae. 

The  SPOROCYSTS,  which  are  produced  direct  from  the  miracidia, 
are  very  simple,  as  all  the  organs  of  the  latter  disappear  during 
or  after  penetration  into  the  intermediary  host,  even  to  the  muscles 
and  excretory  organs,  whereas  the  loosened  and  still  loosening  cells 
of  the  body  continue  to  develop  rapidly.  The  sporocysts  when 
fully  developed  have  the  appearance  of  tubes  or  fusiform  bodies 


144 


THE    ANIMAL    PARASITES    OF    MAN 


with  rounded  edge  ;  they  are  frequently  of  a  yellow  colour.  Their 
length  rarely  exceeds  a  few  millimetres.;  in  some  species  their  size 
increases  exceedingly  through  proliferation,  and  then  occupy  a  large 
portion  of  'the  body  of  the  intermediary  host. 

The  REDIAE  (figs.  78  and  79),  on  the  other  hand,  are  more  cylin- 
drical and  always  have  a  simple  intestine  of  varying  length,  pro- 
vided with  a  pharynx  ;  they  likewise  possess  a  genital  orifice  situated 
at  the  anterior  end  of  the  body  which  serves  for  the  exit  of  the 
cercaria  originating  within  them. 

The  CERCARIA  are  very  different  ;    typically  they  consist  of  the 

anterior  body  and  the  oar-like  tail 
joined  to  the  posterior  end  (fig,  80). 
The  former,  even  to  the  genitals,  has 
the  organisation  of  the  adult  di- 
genetic  trematodes,  and  these  pecu- 
.  •  liarities  allow  the  easy  recognition 
of  that  large  group  to  which  the 
species  in  question  belongs.  On 
the  other  hand,  however,  there  are 
also  organs  that  are  lacking  in  the 
adult  form,  such  as  the  boring 
spine  in  the  oral  sucker  in  many, 
or  the  eyes  situated  on  the  cere- 
b~al  ganglion  ;  moreover,  also,  cu- 
taneous glands  (fig.  80),  the  secre- 
tion from  which  forms  the  cystic 
membrane.  The  oar-like  tail  may 

FIG.  78.-Young     minal  cylinder  (r^     be  long  OT  sh°rt    (stump-tailed    Cer- 

redia  of  the  Liver  dia)  of  Cercaria  caria)  or  entirely  absent  ;  a  fin-like 
*SK2$&  ^nty^nt™:  membrane  may'occur  at  each  side, 
masses  (magni-  tine  («.),  cercaria  or  the  creature  may  be  whorl-like 

fied).          (From     (c.),      germinative  ,     ,  .,,       ,     .   ,-,  •,         <• 

Leuckart.)  bodies    (&.),    and    and   beset  with    bristles  ;    its    free 

-generative   orifice    end    may    be    partly    split   (furcate 

Cercaria),  or  split  to  its  base  (Buce- 

phalus) ;  in  various  forms  also  the  anterior  end  of  the  tail  is  hollow, 
and  has  enclosed  within  it  the  anterior  body,  which  is  otherwise 
free.  The  size  also  of  the  cercaria  belonging  to  the'  different 
species  is  very  diverse  ;  in  addition  to  forms  swimming  in  the 
water  that  have  the  appearance  of  minute  milky-white  bodies, 
there  are  forms  which  measure  as  much  as  6  mm.  in  length. 

The  encysted  forms  (fig.  81)  are  globular  or  oval,  and  are  sur- 
rounded by  a  homogenous  membrane,  which  may  be  striated  or 


TREMATODES  I    BIOLOGY 


145 


contain    granules.      The   tail   is   always   cast   off    when    encystment 
occurs,    and  organs  peculiar  to  the    cercaria    stage    (boring   papilla, 
eyes)    disappear    almost    entirely.       On    the 
other   hand,    the   genitals   appear    or  become 
more   or  less    highly   developed  ;    in    extreme 
cases   to  such   an    extent    that    they   become 
functional,  and  that  after  autocopulation  the 
creatures  produce  ova. 

The  cycle  of  development  of  the  dige- 
netic  Trematodes  has  hitherto  been  gene- 
rally explained  as  a  typical  alternation  of 
GENERATIONS,  one  sexual  generation  regu- 
larly alternating  with  one  or  two  asexually 
reproducing  generations.  Recently,  however, 
a  few  authors  regard  the  cells  from  which 
the  sporocysts  or  rediae  produce  cercariae  as 
parthenogenetically  developing  ova,  and 
the  sporocysts  as  well  as  the  rediae  as  genera- 
tions propagating  parthenogenetically  ;  we 
therefore  speak  of  HETEROGENY,  or  rather 
of  ALLOIOGENESIS,  because  the  former  ex- 
pression should  be  confined  to  the  change  of 
generation  caused  by  sexual  intermediate 
generations,  such  as  occur  in  Rhabdonema 
nigrovenosa. 


nified).  (After  Leuckart.) 


FIG.  80. — The  Cercaria 
of  the  liver  fluke  :  the  cu- 
taneous glands  at  the  sides 

Other    authors,    again,    only    regard    the     of  the  anterior  body  (mag- 
development    of    the    digenea    as    a    compli- 
cated   metamorphosis,    which    is    distributed 
over    several    generations    before    it   is   con- 
cluded. 


BIOLOGY. 


Endoparasitic  Trematodes,  as  fully-devel-  FIG.  81.— Encysted 
oped  creatures,  occur  in  vertebrate  animals 
only,  with  very  few  exceptions  ;  they  inhabit 
almost  all  the  organs  (with  the  exception  of  the  nervous  and 
osseous  systems  and  the  male  genitals),  by  preference  the  intestine 
in  all  its  parts  from  the  oral  cavity  to  the  anus,  and  in  such  a 
manner  that  certain  species  or  groups  inhabit  each  only  certain 
parts  of  the  intestine.  Next  to  the  intestine  other  species  live 
10 


146  THE   ANIMAL   PARASITES    OF   MAN 

in  the  liver,  or  in  its  bile  ducts,  and  in  the  gall-bladder  ;  other 
accessory  organs*  of  the  intestine,  such  as  the  pancreas,  bursa 
Fabricii  (of  birds),  are  only  attacked  by  a  few  species. 
Others  inhabit  the  lungs,  or  the  air  sacks  in  fowls,  a  few  the 
trachea.  Trematodes  have  also  been  known  to  occur  in  the 
urinary  bladder,  the  urethra  and  the  kidneys  of  all  classes  of 
vertebrates ;  they  are  also  present  in  the  vascular  system  of  a 
few  tortoises,  birds  and  mammals  ;  in  birds  they  even  penetrate 
into  the  oviducts,  and  are  occasionally  found  enclosed  in  the 
deposited  eggs  ;  one  species  is  known  to  occur  in  the  cavum 
tympani  and  in  the  Eustachian  tube  of  a  mammal  (Halicore), 
another  in  the  frontal  sinus  of  the  polecat ;  several  kindred 
species  settle  in  the  conjunctival  sac  under  the  membrana  nic- 
titans  of  birds,  one  species  even  lives  in  cysts  of  the  skin  of  singing 
birds.  In  an  analogous  manner  the  monogenetic  trematodes  are  not 
entirely  confined  to  the  surface  of  the  body  or  the  trachea  of  the 
lower  vertebrate  animals  ;  a  few  species  appear  exclusively  in  the 
urinary  bladder,  in  the  oesophagus,  and  in  sharks  also  in  an 
accessory  gland  of  the  rectum. 

.Trematodes  live  free  and  active  within  the  organs  attacked, 
though  they  may  attach  themselves  by  suction  for  a  longer  or  shorter 
period  ;  in  other  cases,  however,  they  bore  more  or  less  deeply  into 
the  intestinal  wall ,  with  their  anterior  end,  or  lie  in  cysts  of 
the  intestinal  wall  which  only  communicate  with  the  lumen 
through  a  small  opening  ;  in  those  species  living  in  the  lungs  of 
mammals  the  host  likewise  produces  a  cyst  which  usually  encloses 
two  specimens  ;  these  double-tenanted  cysts  are  also  observed  in 
other  situations,  and,  though  they  form  the  rule  in  species  sexually 
•distinct,  they  are  not  entirely  confined  to  these.  . 

As  regards  the  AGE  attained  by  endoparasitic  trematodes,  there 
are  but  few  reliable  records,  and  these  differ  considerably ;  the 
overwhelming  majority  of  species  certainly  live  about  a  year,  or 
perhaps  a  little  longer,  but  there  are  some  whose  term  of  life 
extends  to  several  or  many  years. 

Trematodes  are  but  rarely  found  encysted  in  the  higher  verte- 
brate animals  ;  the  condition,  however,  is  more  frequent  in  amphi- 
bians, and  especially  in  fishes,  as  well  as  in  numerous  invertebrate 
animals. 


TREMATODES  I     CLASSIFICATION  147 


CLASSIFICATION  OF  THE  TREMATODES. 

Order  I, — Heterocotylea,  Montic.  Exclusively  ectoparasitic  species,  with  strongly 
developed  clinging  or  clasping  organs,  characterised  by  excretory 
organs  discharging  on  the  dorsal  surface  at  the  anterior  end,  develop- 
ment direct  ;  live  mostly  on  the  body  or  on  the  gills  of  fresh  or  salt- 
water fish,  but  may  also  live  in  the  urinary  bladder  of  amphibians  and 
in  the  oesophagus  of  tortoises. 

Order  II. — Aspidocotylea,  Montic.  Trematodes  with  a  low  organisation 
living  endoparasitically  ;  they  are  distinguished  by  a  large  ventral  sucker, 
the  excretory  organs  discharge  through  a  posterior  pore,  development 
direct  ;  parasitic  in  the  intestine  or  gall-bladder  of  tortoises  and 
marine  fishes,  as  well  as  in  a  few  shell-fish,  especially  in  their  excretory 
organs. 

Order  III. — Malacocotylea,  Montic.  Trematodes,  the  clinging  apparatus  of 
which  as  a  rule  only  consists  of  one  or  two  sucking  discs  (oral  and 
ventral  suckers)  ;  accessory  suckers  are  rare,  and  in  only  one  family — 
the  Holostomidea — a  strongly  developed  clinging  (  apparatus  is  present 
at  the  anterior  end  ;  chitinous  clasping  organs  are  always  lacking.  The 
intestine  is  usually  forked  ;  the  oral  orifice  (with  the  exception  of 
Gasterotomum)  is  situated  at  the  front.  Both  sexual  organs  are  almost 
always  combined  in  the  same  individual  ;  the  genital  pore  is  usually 
on  the  ventral  surface.  The  excretory  organs  discharge  through  a  pore 
at  the  posterior  end.  Always  endoparasitic,  and  living  almost  without 
exception  in  vertebrate  animals,  particularly  in  the  intestine. 

This  order  is  divided  into  two  groups,  ACCORDING  TO  THE  DEVELOPMENT  : 

A.  Metastatica,    Lkt.      Development   without    alternation   of    generations, 

yet  with  the  formation  of  two  larval   forms  and   a  change  of  hosts. 
Fam.    Holostomidea,    with    several   sub-families    and    the    genera   Hemi- 
stomum,   Holostomum,   Diplostomum   and   Polycotyle. 

B.  Digenea   s.   str.,  Lkt.     Development  complicated  by  the  interpolation 

of   generations    that  reproduce  asexually  (sporocysts,    redia)     and  by 
one  or  two  changes  of  host. 

Fam.  Paramphistomidtz,  ventral  sucker  at  the  posterior  end,  the 
excretory  bladder  discharges  on  the  dorsal  surface,  above  the 
acetabulum.  The  genital  pore,  situated  on  the  median  line  of 
the  ventral  surface  is  at  about  a  third  of  the  body  from  the 
anterior  end  ;  the  intestinal  fork  always  without  appendages  ; 
the  pharynx  is  very  near  the  front,  and  is  usually  termed  the 
oral  sucker  ;  hermaphrodites. 
Divided  again  into  several  sub-families  and  genera  (Paramphi- 

stomum,    Gastrothylax,    Gastrodiscus,   &c.). 

Fam.   FasciolidcB,  with  oral  and   ventral  suckers,   excretory   pores  dis- 
charging   at    the    posterior    border  ;    genital    pore    on    the    ventral 
surface,    or    situated    on    the    lateral    or    posterior    border.      The 
intestinal   fork  is  generally   without   appendages  ;   hermaphrodites. 
Divided    into    numerous    sub-families    and    genera,    of    which    only 
Fasciola,   Fasciolopsis,  Paragonimus,   Opisthorchis,   Cotylogonimus 
and   Dicroccelium  interest   us   here. 


148  THE    ANIMAL    PARASITES    OF    MAN 

Fam.    Schistosomidce   resemble    the    Fasciolidce   in    structure,    but    differ 

sexually. 
Genera  :    Schistosomum,    Bilharziella. 

Fam.  DidymozoonidcB ,  a  group  that  is  but  little  known,  and  the 
members  of  which  (Didymozoon,  Nematobothrium}  live  in  pairs 
in  cysts  on  the  exterior  surface  of  the  body  of  marine  fishes  or 
in  the  cavities  of  their  mouth  or  gills  ;  sexually  distinct. 

Fam.  Rhopaliadcs ;  hermaphrodites.  Resemble  the  Fasciolidce  in  their 
organisation.  They  have  an  oral  and  a  ventral  sucker,  with  two 
retractile  rostrella  ;  the  genital  pore  is  rather  forward  and  on 
the  ventral  surface  ;  genital  glands  are  situated  in  the  posterior 
end. 
Genus  :  Rhop alias. 

Fam.  Gasterostomidce,  with  the  oral  orifice  on  the  ventral  surface 
and  a  simple  intestinal  sac.  G aster ostomum  in  the  intestine  of 
fishes.  The  cercaria  stage  termed  Bucephalus  also  belongs  here. 

Fam.  Monostomatidcz,  resemble  the  Fasciolidce  in  their  organisation, 
but  have  only  the  anterior  sucker  ;  the  genital  pore  is  situated 
on  the  anterior  part  of  the  ventral  surface  ;  the  genital  glands  are 
usually  in  the  posterior  third  of  the  body  ;  the  intestinal  fork 
may  be  with  or  without  appendages,  often  again  meeting  at  the 
back  in  the  shape  of  an  arch. 
Divided  into  several  sub-families  and  numerous  genera. 


LITERATURE. 

The    literature   on   Trematodes    is    very    extensive,    but  also  very  scattered;  that 
which  has  been  published  up  to  1892  is  mentioned  and  has  been  utilised  in  my  work 
on  Trematodes  (Braun's  Cl.  u.  Ordn.  d.  Thierr.,  Lpzg.,  vol.  iv.,  part   i ).     Of  the  works 
that  have  appeared  later  the  following  only  need  be  mentioned  here  : — 
BETTENDORF,    H.      Muse.    u.    Sinneszell.   d.    Tremat.   In.-Diss.   Rostock,    1897    (Zool. 

Jahrb.  Anat.,  1897,  part  x.,  p.  307). 

BLOCHMANN,  F.     Die  Epithelfrage  bei  Cest.  u.  Trem.,  Hamburg,  1896. 
BRAUN,  M.     Arten  d.  Gttg.  Clinostomum  (Zool.  Jahrb.  Syst.,  1900,  part  xiv.,  p.  i). 
Tremat.  d.  Chelonier  (Mitth.  zool.  Mus.,  Berlin,  1901,  ii.,  p.  i). 
Tremat.  d.  Chiropt  (Ann.  k.  k.  nat.  Hofmus.,  Wien.,  1900,  xv.,  p.  217). 
Z.  Kenntn.  d.  Trem.  d.  Saugeth  (Zool.  Jahrb.  Syst.,  1901,  part  xiv.,  p.  311). 
Fascioliden  der  Vogel   (ibid.,  1902,  xvi.,  p.  i). 

FISCHOEDER,  F.      Paramphist.  d.  Saugeth.      In.  Diss.,  Kgsbg.,  1902. 
KOWALEWSKI,  M.     Several  works  in  Polish,  but  with  resumes  in  French  or  German, 

in  d.  Sitzber.  d.  Ak.  d.  Wiss.  Krakau. 

LUHE,  M.     Ueb.  Hemiurtden  (Zool.  Anzgr.,  1901,  xxiv.,  p.  394). 

Looss.  A.     Die  Distomen  unsr.  Fische  u.  Frosche.,  Stuttgart,  1894  (BibL.zool.  xVi.)- 
Rech.  faune  paras,  de  1'Egypte,  i.  (Mem.  Inst.  egypt.,   1896,  Hi.,  p.   i). 
Weit.   Beitr.   z.    Kenntn.   Trem.-Fna.   Aeg.    (Zool.   Jahrb.   Syst.     1900     part    xii 

P-  521). 
MONTICELLI,  F.  S.     Stud.  Trem.  endop.,  i.  (Zool.  Jahrb.  Suppl.,  iii.,   1893). 


GASTRODISCUS    HOMINIS  149 


THE   TREMATQDES    OBSERVED    IN    MAN. 

Fare.  i.     Paramphistomidce,  Fischoed. 
Gen.  Gastrodiscus,  Lkt. 

Paramphistomidfs  with  bodies  slender  anteriorly  and  the  posterior  part 
broadened  into  a  disc-like  form  concave  on  the  ventral  surface,  the 
small  ventral  sucker  lying  at  its  posterior  border.  The  pharynx  has 
two  pouch-like  diverticula.  Gastrodiscus  lives  in  the  intestine  'of  the  Equidae 
in  Egypt  and  India  as  well  as  in  man.  [The  species  in  the  horse  is  G.  son- 
sinoi,  Cobbold  (G.  polymastos,  Leuck.).  It  occurs  in  Senegal  and  Quadiloupe. 
It  occurs  from  pharynx  to  anus  and  in  the  nasal  fossae. — F.  V.  T.] 

Gastrodiscus  hominis  (Lew.  and  McConn),  1876. ] 
Syn.,  Amphistomum  hominis,  Lew.  and  McConn. 

The  body  when  fresh  is  of  a  reddish  colour  ;  it  measures  5 — 
8  mm.  in  length,  3 — 4  mm.  in  breadth,  and  presents  a  large  circular 
disc  at  the  posterior  border  of  which  the  small 
sucker  is  situated  (fig.  82)  ;  the  genital  pore  is 
on  a  level  with  the  bifurcation  of  the  intestine  ; 
the  generative  organs  consist  of  the  two  lobate 
testes,  a  sinuous  vas  deferens,  the  uterus, 
and  the  vitelline  sacs  placed  laterally  ;  parts 
of  the  nervous  and  excretory  system  have  also 
been  seen.  The  eggs  are  oval  and  measure 
FIG.  82.—Gastro-  0*150  mm.  in  length  by  0*072  mm.  in  breadth. 

•discus       hominis, 

slightly    magnified.  This  parasite  has   hitherto  only    been  observed  twice 

(After  Leuckart.)          in  human  beings,  in  an  Assamese  and  in   an   Indian,  and 

was  present   in  the  caecum  and  colon  in  large  numbers  ; 

it   is  doubtless  only  incidentally  a  parasite    of    man,    its    normal    host   being 
some  Indian  mammal. 

.      Fam.  2.     Fasciolidre,  Raill. 
Gen.  i.     Fasciola,  L.,  1758.     . 

Large  Fasciolidae  with  leaf-shaped  bodies,  the  anterior  end  of  which  is 
shaped  into  a  conical  head.  The  ventral  sucker  is  situated  near  the  mouth, 
and  is  large  and  powerful.  The  cuticle  is  covered  with  spines  ;  the  oesopha- 
gus is  short,  the  pharynx  is  well  developed  ;  the  intestine  bifurcates  near 
the  median  line  and  extends  far  backwards  ;  the  intestinal  caeca  are  provided 
with  numerous  long  lateral  and  fewer  and  shorter  median  branches.  The 
excretory  system  is  much  ramified,  and  the  long  terminal  part  is 

1  Lewis,  T.  R.,  and  McConnel,  "  A  New  Para.  aff.  Man  "  (Proc.  Asiat.  Soc.,  Bengal  /., 
1876,  p.  182). 


THE   ANIMAL   PARASITES    OF    MAN 


cylindrical.  The  genital  pore  is  situated  in  the  median  line  anterior 
of  the  ventral  sucker.  The  ovary  is  on  one  side  of  the  body  in 
front  of  the  testes.  It  has  many  ramifications,  as  have  also  the  testes, 
which  lie  obliquely  one  behind  the  other.  The  uterus,  in  the  shape  of  a 
rosette,  lies  in  front  of  the  sexual  glands  ;  the  vitelline  sacs  at  the  sides 
and  in  the  posterior  end  are  amply  developed  in  both  directions.  Laurer's 
canal  is  .present,  but  there  is  no  receptaculum  seminis  ;  the  vesicula  semi- 
nalis  is  situated  in  the  cirrus  pouch  ;  the  ova  are  large,  not  very  numerous, 
and  only  develop  after  they  have  been  deposited.  This  parasite  infests  the 
biliary  ducts  of  herbivorous  animals. 

I.    Fasciola  kepatica,  L.,   1758. 

Syn.  :  Distomum  hepaticum,  Retz.,   1786;  Fasciola  humana,  Gmel.,  1789; 
Distomum  cavies,  Sons.,    1890  ;    Cladoccelium  hepaticum,   Stoss.,    1892. 

Length  20 — 30  mm.,  breadth  8 — 13  mm., 
head-cone  4 — 5  mm.  in  length  and  sharply 
differentiated  from  the  posterior  p^art  of  the 
body.  Spines  in  altern citing  transverse  rows 
and  extending  on  the  ventral  surface  to  the 
posterior  border  of  the  testes,  and  on  the 
dorsal  surface  not  quite  so  far.  The  spines 
are  smaller  on  the  head  cone  than  on  the 
posterior  part  of  the  body,  where  they  are 
discernible  with  the  naked  eye.  The  suckers 
are  hemispherical,  and  near  each  other ;  the 
oral  sucker  is  about  i  mm.  and  the  ventral 
sucker  about  r6  mm.  in  diameter.  The 
pharynx,  which  includes  almost  the  entire 
oesophagus,  measures  07  mm.  in  length,  and 
o-4  mm.  in  breadth.  The  intestine  bifurcates 
in  the  head-cone  and  the  branches  are  even 
here  furnished  with  blind  sacs  directed  out- 
wardly. The  ovary  is  ramified  and  situ- 
ated in  front  of  the  transverse  vitello  duct ; 

FIG.  83.  —  Intestine  of  *ne  shell-glands  lie  near  the  ovary  in  the 
median  line  ;  posterior  to  the  transverse  vi- 
tello duct  are  the  greatly  ramified  testes, 
which  occupy  the  greatest  portion  of  the 

posterior  part  of  the  body,  with  the  exception  of  the  lateral  and 
posterior  border  ;  the  vasa  efferentia  only  unite  at  the  entry  into 
the  cirrus  pouch.  The  vitellaria  occupy  the  sides  of  the  pos- 
terior part  of  the  body  commencing  at  the  level  of  the  ventral 
sucker  and  uniting  behind  the  testes.  The  ova  are  yellowish-brown, 


Fasciola  hepatica,  L.  5/1. 
From  a  specimen  that  is 
not  yet  pubescent. 


FASCIOLA    HEPATICA 


ova],  with  cap-like  lid,  0*130 — 0*145  mm.  in  length,  0*070 — 0*090  mm. 
in  breadth   (average   size  0*132 — 0*070). 

The  Liver  Fluke  inhabits  the  bile  ducts  of  numerous  herbi- 
vorous mammals  (sheep,  ox,  goat,  horse,  ass,  rabbit,1  guinea-pig, 
squirrel,  beaver,  deer,  roe,  antelope,  camel,  kangaroo,  and  others, 
and  is  distributed  over  the  whole  of  Europe,  though  not  to  an 
equal  extent.  It  is  further  known  in 
North  Africa,  in  N.  and  S.  America, 
as  well  as  in  Australia  ;  it  is  also 
found  in  Asia,  as  it  has  been  re- 
ported from  Japan  and  China.  In 
some  districts  of  Germany  it  is 
very  frequent  and  the  slaughter- 
house reports  of  various  places 
show  that  it  is  of  daily  occurrence.  . 

[The  liver  fluke  also  occurs  in 
Tasmania.  In  India  it  has  been 
found  in  the  buffalo.  In  Burmah 
it  is  found  impossible  to  keep 


v.  s. 


E.d. 


FIG.  84. — Fasciola  hepatica,  natural  size 
(Mull,  fluid,  alcohol,  creosote,  Canada  bal- 
sam). E.d.,  Excretory  duct  of  the  vitelline 
sacs;  V.s.,  vitelline  sacs;  M.,  mouth;  Tr.c., 
transverse  canals;  Ut.,  uterus. 


FIG.  85.  —  Fasciola  hepatica,  L., 
with  sexual  apparatus.  /.,  intestine  ; 
V.s.  vitelline  sacs  ;  Ov.,  ovary;  O.,  oral 
aperture  ;  Ut.,  uterus  ;  S.,  ventral 
sucker;  T.,  testes.  (After  Glaus.)  jg 


sheep  owing  to  its  ravages  ("  A  Treatise  on  the  Diseases  of 
Sheep,"  1890,  p.  136,  Steel).  According  to  Hamont  (the 
Veterinarian,  vol.  vii.,  pp.  557,  587)  the  annual  fall  of  the  Nile 
causes  the  loss  from  "  rot "  of  160,000  sheep.  This  parasite  is 


1  [There  does  not  seem  to  be  any  direct  evidence  of  either  rabbits  or  hares  normally 
being  invaded  by  this  Fluke. — F.  V.  T.] 


152  THE    ANIMAL    PARASITES    OF    MAN 

said  to  have  been  introduced  into  Australia  in   1855   by  imported 
rams  sent  from  Germany  to  Victoria. — F.  V.   T.] 

The  liver  fluke,  however,  is  by  no  means  a  harmless  parasite, 
for  it  produces  in  domestic  animals,  more  especially  in  sheep, 
a  disease  of  the  liver  that  appears  epidemically  in  certain  years 
and  districts,  and  commits  great  ravages  amongst  the  flocks. 

[The  following  records  show  the  enormous  loss  caused  in  sheep 
by  this  parasite.  In  1812,  in  the  Midi,  principally  in  the  Depart- 
ments of  the  Rhone,  Herault,  and  Gard,  the  disease  was  rampant ; 
300,000  sheep  perished  in  the  Aries  territory,  and  90,000  in  the 
arrondissements  of  Nimes  and  Montpellier.  In  1829  and  1830,  in 
the  Department  of  the  Meusc  and  near  localities,  not  only  sheep 
but  oxen  died  in  enormous  numbers  ;  for  instance,  in  the  arron- 
dissement  of  Verdun  out  of  50,000  sheep  20,000  died,  and  out  of 
20,000  cattle  2,200  died.  In  England,  in  1830,  2,000,000  sheep 
were  carried  off;  whilst,  in  1862,  60  per  cent,  of  the  sheep  died  in 
Ireland  ;  and  in  1879  over  300,000  were  lost  in  England  ;  whilst  as 
late  as  1891  one  owner  in  the  same  country  lost  over  10,000 
sheep  (Live  Stock  Journal,  October  30,  1891).-  F.  V.  T.] 

The  disease  usually  commences  towards  the  end  of  summer 
with  an  enlargement  of  the  liver,  induced  by  the  invasion  of 
numerous  young  flukes  ;  in  the  autumn  and  winter  the  animals 
suffer  from  the  consequences  of  disordered  biliary  secretion  ;  they 
become  feverish,  emaciated  and  ana-mic,  and  lose  their  appetite. 
In  consequence  of  the  consecutive  atrophy  of  the  liver  cedema 
and  ascites  set  in  and  many  animals  succumb  to  this  "  liver  rot." 
On  examination  the  liver  is  found  to  be  shrunken,  the  bile  ducts 
are  enormously  dilated,  and  in  parts  contain  sacculations  full  of 
hepatic  flukes.  Should  the  animals  survive  this  stage,  a  spon- 
taneous recovery  ensues  in  consequence  of  the  flukes  commencing 
to  leave  the  liver  in  the  spring,  but  the  liver  remains  altered  and 
its  sale  is  prohibited  l  when  the  changes  are  extensive.2 

[The  following  stages  may  be  noticed  in  sheep  suffering  from 
distomatosis.  Gerlach  recognised  four  stages,  based  -  on  the  varied 
relations  that  the  flukes  contract  with  the  liver  of  their  host. 


1  [This  is  not  the  case  in  Great  Britain  ;  Fluky  sheep  are  sent  to  market  ;  there  being 
no  danger  to  man  eating  the  flesh. — F.  V.  T.] 

2  As  an  example,  this  occurred  in  Berlin  in  the  case  of  19,034  oxen,  15,542  sheep, 
i, 704  pigs,  and  160  calves  in  the  period  of  1883-1893  ;  during  which  time  719,157  oxen, 
1,519,003  sheep,   2,258,110  pigs,  and   567,964  calves  were  slaughtered.     As  a  matter 
of  fact,  however,  the  number  of  infected  beasts  was  really  larger. 


FASCIOLA    HEPATICA  153 

These  periods  are  sometimes  very  marked,  but  at  others,  owing  to 
subsequent  *  infestations,  the  features  become  merged  and  so 
obliterated.  But  when  a  single  infestation  occurs  they  are  very 
marked. 

The  first  period  is  called  the  PERIOD  OF  IMMIGRATION.  This 
occurs  at  the  fall  of  the  year  and  generally  passes  unperceived,  as 
the  young  flukes  do  little  harm  to  the  liver.  It  varies  from  four 
to  thirteen  weeks.  Gerlach  has  remarked  upon  cases  of  death 
from  apoplexy  at  this  period. 

The  second  period  is  the  PERIOD  OF  ANEMIA.  This  occurs  in 
November  and  December.  The  sheep  at  first  fatten  rapidly,  but 
later  their  mucous  membranes  become  pale  and  of  a  yellowish  hue, 
and  they  become  sluggish  and  cease  to  feed.  The  faeces  are  normal, 
but  may  contain  fluke  ova. 

b. 


FIG.  86. — Egg  of  Fasciola  hepatica,  L.  FIG.  87. — Limnceus  minutus,  the  inter- 

240/1.     At  the  lid-end  the  yolk  cells  may       mediary  host  of  the  Liver  Fluke,    a,  natu- 
be  observed  through  the  shell.  ral  size;  b,  magnified.    (From  Leuckart.) 


The  third  period  is  the  PERIOD  OF  WASTING.  This  corresponds 
with  the  beginning  of  January — about  three  months  after  the 
entry  of  the  larva?.  Emaciation  now  becomes  very  marked,  the 
skin  and  mucous  membranes  blanched,  temperature  variable  and 
marked  by  an-  irregular  curve  ;  respiration  laboured  and  quick  ; 
appetite  regular ;  abortion  frequently  occurs  in  pregnant  ewes  ; 
pressure  on  the  back  causes  the  animals  to  fall  ;  local  oedemas 
occur,  the  most  perceptible  in  the  submaxillary  space,  extending 
below  the  larynx  and  over  the  cheeks  and  parotids  (called 
"  bourse,"  "  boule,"  in  France  ;  "  watery  poke  "  or  "  cockered  "  in 
England).  Death  usually  occurs  at  this  period,  but  a  fourth 
stage  may  occur. 

The  fourth  period  is  the  PERIOD  OF  EMIGRATION  OF  THE 
FLUKES,  This  is  a  period  of  convalescence  and  recovery,  generally 
in  May  and  June. — F.  V.  T.] 


154  THE  ANIMAL    PARASITES    OF   MAN 

Oxen  suffer  less  in  general,  but  even  in  these  animals  "  stray  " 
hepatic  flukes  are  occasionally  found  in  the  lungs,  enclosed  in  thick- 
walled  cysts. 

The  HISTORY  OF  THE  DEVELOPMENT  of  the  liver  fluke  has  been 
discovered  by  R.  Leuckart  and  P.  Thomas.  According  to  these 
investigators  the  elongated  miracidium  (fig.  75),  ciliated  all  over, 
develops  from  the  eggs  of  the  liver  fluke  a  few  weeks  after  the" 
latter  (figs.  74,  86)  have  reached  the  water,  and  after  it  has  become 
free,  the  embryo  penetrates  a  water-snail  (Limnseus  truncafulus, 
Mull,  —  L.  minutus,  Drap.)  that  is  common  in  fresh  water,  and 
can  live  in  the  smallest  collection  of  water  as  well  as  in  meadows 
that  have  been  flooded,  and  becomes  a  sporocyst  (fig.  77). 
The  sporocyst  first  of  all  produces  rediae,  which  remain  in  the 
same  host,  and  under  •  certain  circumstances  it  develops  a  second 
generation  of  rediae  and  finally  forms  cercaria  (fig.  80).  The 
latter  become  encysted  on  the  meadows  and  are  taken  up  by  the 
respective  hosts  with  their  food  ;  this  takes  place  towards  the  end 
of  summer,  while  the  sheep  feeding  on  the  pasture  land  in  the 
spring  spread  the  eggs  of  the  hepatic  fluke,  and  sometimes  the 
entire  animal,  by  passing  them  with  their  faeces. 

In  districts  where  Limnceus  minutus  is  absent,  analogous 
species  act  as  the  intermediary  hosts,  of  which  one  example, 
according  to  Lutz,  is  the  Limncem  oahuensis l  in  the  Sandwich 
Islands. 

[The  host  in  Europe  is  Limnceus  truncatulus.  This  snail 
extends  from  Siberia  to  Algeria  and  Sicily,  and  according  to 
Captain  Hutton  is  a  native  of  Afghanistan.  It  also  occurs  in 
Thibet,  Amoor,  Morocco,  Tunisia,  Canary  Islands  and  the  Faroe 
Islands.  It  deposits  its  eggs  or  spawn  upon  the  mud  around 
ponds,  ditches,  and  streams.  The  eggs  are  laid  in  batches  of 
thirty  to  a  hundred,  each  snail  laying  as  many  as  1,500  eggs  ; 
they  are  united  into  strips  of  a  gelatinous  substance.  In  about 
two  weeks  young  snails  appear.  It  is  amphibious,  being  more 


1  The  most  important  literature  is  as  follows  :  Stieda,  L.,  "  Beitr.  z.  Anat.  d.  Plattw. 
I."  (Arch.  f.  An.  u.  Phys.,  1867,  p.  52);  "  Ueb.  d.  angebl.  inn.  Zusammenh.  d.  mdnnL 
u.  weibl.  Org.  bei.  Trent."  (Ibid.,  1871,  p.  31);  Sommer,  L.,  "Anat.  d.  Lebereg."  (Z.  f.  w. 
Zool.,  1880,  xxxiv.,  p.  539);  Mace,  E.,  Rech.  anat.  sur  la  grande  douve  du  foie.  These 
de  Nancy,  Paris,  1882  ;  Leuckart,  R.,  "  Z.  Entw.  d.  Lebereg."  (Arch.  f.  Naturg.,  1882, 
i.,  p.  80);  Thomas,  P.,  "The  Life  Hist,  of  the  Liver-Fluke"  Quart.  Journ.  Micr. 
Sc.,  1883,  xxiii.,  p.  99);  Schaper,  "  Die  Leberegelkrankh.  d.  Schafe"  (Dtsch.  Ztsch. 
/.  Thiermed.,  1889,  xvi.);  Lutz,  A.,  "  Z.  Lebensgesch.  d.  Disl.  hep"  (C.  f.  B.  u.  P., 
xi.f  p.  783  ;  xiii.,  p.  320);  Coe,  W.  R.,  "  Bau  des  Embr.  v.  Dist.  hep."  (Zool.  Jahrb. 
Abth.,  ix.,  p.  561);  Havet,  J.,  "  Contrib.  al'etud.  d.  syst.  nerv.  d.  trem."  ("Cellule," 
1900,  xvii.,  p.  351). 


FASCIOLA    HEPATICA  155 

frequently  met  with  out  of  the  water  than  in  it.  It  occurs  in 
elevated  spots  as  well  as  in  low-lying  districts.  Moquin-Tandon 
found  it  at  4,000  feet  in  the  Pyrenees.  In  the  allied  species, 
L.  peregra,  the  fluke  will  develop  up  to  a  certain  stage,  but  never 
completes  all  its  varied  phases. 

In  South  America  the  host  is  probably  Limnceus  viator,  Orb., 
and  in  North  America,  L.  humilis,  Say. — F.  V.  T.] 

In  human  beings  as  well  as  in  some  of  the  mammals  quoted 
above,  the  liver  fluke  is  only  a  casual  parasite,  and  hitherto  only 
twenty-three  cases  have  been  observed  in  man  l ;  the  infection  was 
mostly  a  mild  one  and  there  were  no  disturbances,  or  only  very 
trifling  ones ;  a  few  isolated  cases  were  only  discovered  post 
mortem.  Occasionally,  however,  even  when  the  infection  was 
inconsiderable,  severe  symptoms  were  set  up,  which  in  isolated 
cases  led  to  fatal  issue.  The  symptoms  observed  (enlargement 
and  painfulness  of  the  liver,  icterus)  certainly  only  indicated  a 
disease  of  the  liver. 

As  the  liver  fluke  feeds  on  blood  it  is  possible  that  it  also 
reaches  the  circulatory  system,  particularly  when  young,  and  cases 
have  been  known  in  which  it  has  been  carried  into  organs  far 
from  its  original  situation  by  the  blood.  Such  cases  also  have 
been  repeatedly  observed  in  man  ;  probably  the  parasite  described 
by  Treutler,  1793,  as  a  Hexathyridium  venarum>  which  protruded 
from  the  ruptured  vena  tibialis  antica  of  a  man,  was  a  young 
liver  fluke.  A  few  adult  specimens  were  found  by  Duval  in  the 
portal  vein  and  other  blood-vessels  at  an  operation  or  post  mortem 
at  Rennes  (1842)  on  a  man,  aged  49,  and  a  similar  statement  is 
reported  by  Vital  from  Constantine  (1874).  Giesker,  in  1850, 
found  two  hepatic  flukes  in  a  swelling  on  the  sole  of  the  foot  of 
a  woman.  Penn  Harris  states  that  he  observed  six  specimens  in 
Liverpool  which  were  present  in  a  spontaneously  burst  abscess  of 
the  occiput  of  a  two-months-old  infant.  Another  case  which,  like 
the  previous  one,  is  reported  by  Lankester,2  relates  to  a  sailor 
who  suffered  from  an  abscess  behind  the  ear,  and  from  which  a 
liver  fluke  was  expelled.  Finally,  Dionis  de  Carrieres  8  reports  the 

1  Casuistic  of  Davaine  (Traite  des  entoz.,  1877,  2nd  edit.,  p.  253)  ;  R.  Blanchard 
(Trait?,  de  Zool.  med.,  1889,  i.,  p.  589),  and  R.  Leuckart  (Die  menschl.  Paras.,  2nd  edit., 
vol.  ii.,  p.  316),  which  works  also  mention  the  literature  ;  also  in  Huber's  Bibliogr. 
d.  klin.  Helm.  (Miinchen,  1895).  Case  23  is  quoted  by  Malherbe  (Progr.  med.,  1898, 
vii.,  No.  4). 

'-'  In  the  English  translation  of  Kuchenmeister's  work  on  Parasitology  (London, 
1857).  The  specimen  is  preserved  in  the  Hunterian  Museum,  London,  and  is  a  pubes- 
cent liver-fluke,  measuring  18  mm.  in  length  and  7  mm.  in  breadth. 

3  Communicated  by  Davaine  (I.e.). 


156 


THE    ANIMAL    PARASITES    OF    MAN 


case  of  a  man  aged  35,  in  whose  right  hypochondriac  region  a 
tumour  the  size  of  a  pigeon's  egg  had  formed,  and  from  which  a 
young  liver  fluke  was  extracted. 

After  such  experiences  it  is  not  improbable  that  Distomum  oculi 
humani,  Ammon,  1833,  as  well  as  Monostomum  lentis,  v.  Nordm., 
1832,  may  have  been  very  young  hepatic  flukes  that  had  strayed. 
Ammon  found  four  specimens  (length  0.5-1  mm.)  of  his  species 
(termed  Distomum  ophthalmobium  by  Diesing  in  1850)  between  the 
opaque  lens  and  the  capsule  of  a  five-months'-old  child .  in  Dresden, 
and  von  Nordmann  discovered  the  Monostomum  lentis  to  the  number 
of  eight  specimens  (only  0*3  mm.  in  length)  in  the  opaque  lens  of 
an  old  woman,1  The  fact  that  Ammon  found  that  the  intestinal  caeca 


FIG.  88. — Young  Fasciola  hepatica,  soon 
after  travelling  into  the  liver  :  the  intestinal 
forks  carry  lateral  blind  ducts  (magnified). 
(From  Leuckart.) 


FIG.  89. — Fasciola  hepatica  var. 
angusta,  Raill.  (natural  size).  (After 
Stiles  and  Hassall.) 


of  the  worm  discovered  by  him  had  no  lateral  branches  does  not 
oppose  the  above  opinion,  as  in  the  liver  fluke  the  intestinal  caeca 
are  originally  unbranched,  and  according  to  Lutz  they  only  later 
develop  lateral  ramifications  between  the  twelfth  and  twenty-second 
day  of  the  infection  (fig.  88). 

2.  Fasciola  hepatica  var.  angusta,  Raill.,  1895. 

Under  this  name  Raillet 2  describes  elongated  and  slender  flukes 
which  occur  in   the  bile  ducts   of   oxen    slaughtered  at   Saint  Louis 


1  Gescheidt  and  Ammon,  "  Die  Entoz.  d.  Auges"  (Ztsch.  f.  Ophth.,  1833,  iii.,  p.  405); 
Ammon,  Darst.  d.  Krankh.  d.  menschl.  Aug.  Dresd.,  1838);  Nordmann,  A.  v., 
Mikrogr.  Beitr.  z.  Naturg.  d.  wirbellos.  Thiere.,  Berlin,  1832,  part  ii.,  p.  ix. 


-  Railliet,  A.,  "  Sur  une  form,  part  de  douve 
Paris,   1895  [10],  ii.,  p.  388). 


>.  prov.  du  Senegal  "  (C.  R.  soc.  biol., 


FASCIOLA    HEPATICA    VAR.    ANGUSTA        ..  157 

(Senegal),  and  which  are  distinguished  from  the  European  liver 
fluke  by  their  more  elongated  shape,  lesser  breadth  (in  their  con- 
tracted state  26-^38  mm.  in  length,  6 — 8  mm.  in  breadth),  short 
anterior  cone,  larger  ventral  sucker  and  larger  eggs  (0*143 — 0*151 
mm.  in  length,  0*082 — 0*088  in  breadth,  average  size  0*147:0*082 
mm.). 

An  analogous  form  from  the  bile  ducts  of  slaughtered 
animals  of  Egypt  (buffaloes,  oxen,  sheep  and  goats)  has  been 
described  by  Looss l  as  var.  cegyptiaca,  and  later,  like  Railliet's 
variety,  was  declared  to  be  an  independent  species  (Fasciola  angusta, 
Fasc.  cegyptiaca).'2 

As  now  the  ordinary  hepatic  fluke  (Fasciola  hepatica,  L.)  is 
known  to  invade  man,  this  may  likewise  be  the  case  in  analogous 
forms,  which  would  then  probably  develop  in  a  similar  manner. 

As  a  matter  of  fact,  an  observation  exists  that  confirms  this 
supposition.  A  medical  man,  H.  de  Gouvea,3  observed  a  French 
naval  officer  in  Rio  de  Janeiro  who  was  suffering  from  fever, 
cough  and  slight  haemoptysis  ;  the  lungs  appeared  to  be  intact 
except  for  a  sharply  circumscribed  spot  at  the  base  of  the  left 
lung  ;  twenty  days  later  the  patient,  during  an  attack  of  coughing 
associated  with  haemoptysis,  expectorated  a  fluke  25  mm.  in 
length,  which  was  distinguished  by  its  slender  form  and  the  size 
of  its  ventral  sucker,  which  was  situated  close  to  the  oral  sucker. 
The  author  himself  called  attention  to  the  resemblance  of  the 
worm  to  the  flukes  which  inhabit  the  liver  of  Egyptian  buffaloes. 

Taking  into  consideration  the  fact  that  de  'Gouvea's  patient  had 
made  a  stay  of  several  weeks  in  Dakar  (Senegambia)  during  July 
of  the  same  year,  where  Fasciola  hepatica  var.  angusta  occurs 
amongst  cattle,  and  considering  also  the  peculiarities  of  the  worm 
observed  by  de  Gouvea,  Railliet  (I.e.)  is  inclined  to  regard  the  two 
forms  as  identical,  and  no  objection  to  this  opinion  can  be  advanced. 

But  in  1856  Cobbold  described  a  species  found  in  the  liver 
of  the  giraffe  which  he  named  Fasciola  gigantica,  and  which 
attained  a  length  of  75  mm.  and  a  breadth  of  from  4 — 12  mm. 
It  is  nearly  related  to  Looss'  and  Railliet's  varieties,  which  are 
hardly  distinguishable  one  from  the  other ;  it  is  likewise  very 
long  and  narrow,  the  lateral  borders  of  the  posterior  part  of  the 


1  Looss,  A.,  "  Reck,  faune  par.  de  I' Eg."  (Mem.  Inst.  egypt.,  1896,  iii.,  p.  33). 

-  Looss,  A.,  "  Obs.  a  prop,  d'une  note     .     .     .     ."    (C.  f.  B.,  P.  u.  L,  1898  [i],  xxiii., 
p.  459). 

3  Gouvea,  H.  de,  La  distomatose  pulm.  par  la  douve  du  foie  These  (Paris,  1895). 


158 


THE    ANIMAL    PARASITES    OF    MAN 


Ut.n 


Cp. 


body  run  almost  parallel,  the  head  cone  is  short,  the  large  ventral 
sucker  very  prominent  and  very  close  to  the  oral  sucker,  while  the 

eggs  measure- 0*145— 0*150  mm. 
in  length  by  0*082  —  0*088  in 
breadth.  On  the  strength  of 
these  characters  R.  Blanch ard 1 
regards  the  flukes  living  in  the 
Senegambia  oxen  and  in  the 
Egyptian  buffalo  as  belonging  to 
Fasciola  gigantica,  Cobb.,  and 
likewise  includes  the  species  from 
de  Gouvea's  case. .  This  may  be 
so,  but,  apart  from  the  different 
size  of  the  body  there  remain 
peculiarities  which,  if  the  de- 
scriptions are  correct,  indicate 
a  difference  of  species. - 


Gen.  2.  Fasciolopsis,  Looss, 
1898. 

No  head  cone  ;  cuticle  without 
spines,  ventral  sucker  large  and 
elongated  posteriorly  into  the  shape 
of  a  sack ;  the  intestinal  branches 
are  not  ramified.  The  testes  lie  in 
the  posterior  half  of  the  body  and  are 
much  branched.  Cirrus  pouch  long 
and  cylindrical,  its  greatest  length 
being  occupied  by  the  sinuous  tubular 
seminal  vesicle,  on  which  a  blind 
duct  is  developed.  The  ovarium 
is  ramified  ;  Laurer's  canal  present. 
The  oviducts  occupy  almost  the  whole 
of  the  sides  of  the  bodv. 


FIG.  90. — Fasciolopsis  buski  (Lank), 
(magnified).  Vs.,  Ventral  sucker  ;  Cp., 
cirrus  pouch  ;  /.,  intestinal  fork  ;  Sv., 
vitelline  sac  ;  T.,  testes  ;  O.,  ovarium  ; 
Ms.  mouth  sucker  ;  Shg.,  shell  gland  ; 
Ut.,  uterus.  (After  Odhner.) 


1  Blanchard,.R.,   "Mai.  paras.,  par  an."   (Traite  de  path.  s>en.    [Bouchard],    1895, 
"..  P.  733-  ) 

2  Illustrations  of  Cobbold's  species  may  be  seen  in  "  Cobbold's  Entozoa  ".(London, 
1864),  plate  i,  reproduced  in  Braun's  Cl.  u.  Ord.  d.  Thierr.,  vol.  iv  ;    plate  i  in  Jo-urn, 
comp.  med.  and  vet.  arch.,  1895,  P-  I4I>  and  in  U.S.  Dep.  of  apr.  Bur.  of  an  Ind.  Bull., 
No.  19,  Wash.,  1898,  p.  50,  fig.  27.     An  illustration  of  the  Egyptian  form  may  be  seen 
in  Looss  (I.e.,  plate  3,  fig.  16),  and  has  been  reproduced  in  the  Bull,  quoted.    No.  19., 
fig.  26,  represents  Railliet's  form  (ibid.,  figs.  23  and  24,  original). 


FASCIOLOPSIS    BUSKI 


159 


Fasciolopsis  buski  (Lank.),  1857. 

Syn. :    Distomum    buski,    Lank.,    1857;    Dist.    crassum,    Busk,    1859,   nee 

v.  Sieb,  1836. 

The  length  of  the  body  varies  ;  it  may  measure  24 — 37  or  even 
attain  70  mm. ;  the  breadth  is  from  5-5  to  12 — 14  mm.  The  oral 
sucker  measures  o-5  mm.  in  diameter,  the  ventral  sucker  is  three 
to  four  times  as  large  ;  the  pharynx  is  globular,  0*7  mm.  in  diameter  ; 
the  prepharynx  is  provided  with  a  sphincter ;  the  intestinal 
branches  extend  to  the  posterior  border.  The  genital  pore  is  at 
the  anterior  border  of  the  ventral  sucker ;  the  tubular  cirrus 
pouch  is  about  one-fourth  of  the  length  of 
the  body.  The  ovary  and  shell  glands  are 
situated  in  about  the  middle  of  the  body  with 
the  testes  behind  them,  and  the  uterus  in 
front.  The  vitelline  sacs  extend  from  the 
ventral  sucker  to  the  posterior  border.  The 
eggs  measure  0-12 — 0*130  mm.  in  length  and 
°'°77 — °'°8  mm.  in  breadth. 

This  species  has  hitherto  only  been  ob- 
served in  the  intestine  of  man,  and  then 
only  in  East  and  South  Asia  (Budd,  Lan- 
kester,  Leidy,  Cobbold,  Odhner).  seven  cases 
representing  the  total. 


Distomum  rathouisi,  Poirier,  1887 


, 


is   related    to    the    above   but    not   identical 
with  it.     It   measures  25   mm.  in  length,   by 


FIG.  91.  —  Distomum 
rathouisi  (Poir.).  The 
mouth  at  the  top,  and 
under  it  the  genital  pore 
and  ventral  sucker,  behind 
which  again  is  the  uterus. 
The  vitelline  sacs  are  at 
the  sides,  and  posteriorly 


, 

1 6  mm.   in  breadth,  and  the  contour  is  oval     in   the  central  field  the 
with   a   slightly  prominent   head  cone;      the     [sa™fifronf of  'tte °dgM 
cuticle  has   no  spines,   the   suckers   are  near     one.    (After  ciaus.) 
to    each     other,    the    oral   sucker    measuring 

i -5  and  the  ventral  sucker  2  mm.  in  diameter.  The  intestines 
have  no  lateral  branches  ;  the  testes  and  ovary  are  situated  in  the 
posterior  half  of  the  body,  the  branched  testes  are  side  by  side, 
the  ramified  ovary  is  in  front  of  one  testis  and  behind  the  trans- 
verse vitello  duct.  The  vitelline  sacs  occupy  almost  the  entire 
sides,  of  the  body  and  do  not  meet  at  the  back.  The  uterus  is 
in  the  central  field  of  the  anterior  half  of  the  body.  The  genital 
pore  is  close  in  front  of  the  ventral  sucker.  Eggs  0-15 — o-8o  mm. 
Hitherto  this  parasite  has  only  been  observed  once — in  a  Chinese 


160  THE    ANIMAL    PARASITES    OF    MAN 

woman  who  evacuated  the  specimen  described,   after  violent  pains 
in   the   hepatic   region. 

According  to  a  written  communication  by  P.  Manson  to  R. 
Blanchard,  two  further  cases  (which  species-?)  have  been  observed 
in  North  Borneo,  the  host  of  one  being  a  Chinaman  and  the 
other  a  Malayan.  Nothing  is  known  about  the  development  of 
either  species. 

LITERATURE    OF    D.    BUSKI. 

BUDD,  G.     On  Diseases  of  the  Liver.     Lond.,   1852. 

LANKESTER,  E.     In  Manual  of  An.  and  Veg.  Paras.  (Kiichenmeister).     Lond.,   1857, 

i.,  App.  B.,  p.  437. 

LEIDY,  J.     On  Dist.  Hepatic.     (Proc.  Ac.  Nat.  Sc.,  Philad.,  1873,  p.  364.) 
COBBOLD,  T.  SP.     On  the  supposed  rarity  of     ....     of  Dist.  crassum.     (Journ. 

Linn.  Soc.,  1875,  xii.,  p.  285.)     Obs.  on  the  large  human   fluke     .     .     .     (The 

Veterin.,  1876.) 
ODHNER,  TH.     Fasciolopsis  buski.     .     .     (C.   f.   B.,   P.   u.    I.   [i],    1902,   xxxi.,   Orig., 

P-  573-) 

POIRIER,  P.     Dist.  rathouisi  Not.  s.  une  nouv.  esp.  de  dist.  par.  de  ITiomme.     (Arch, 
zool.  exp.  et  gen.,  1887  [2],  v.,  p.  203.) 

[According  to  Scheube  ("  Diseases  of  Warm  Climates,"  Second 
Revised  Edition),  Distomum  buski,  Lank,  (i.e.,  Fasciolopsis  buski, 
Lank.),  is  the  same  as  D.  rathouisi,  Poirier,  and  D.  crassum, 
Busk,  and  occurs  in  Selangor  and  Assam. — F.  V.  T.] 

Gen.  3.  Paragonimus,  Braun,  1899. 

Fasciolidae,  with  thick  oval  or  broad  fusiform  bodies,  the  transverse 
section  of  which  is  almost  circular.  The  cuticle  has  scale-like  spines. 
The  suckers  are  at  a  distance  of  ha.lf  the  length  of  the  body  from  each 
other  ;  the  oesophagus  is  short,  the  pharynx  almost  globular  ;  the  intestinal 
caeca  have  no  lateral  branches,  and  run  in  a  zig-zag  manner  to  the  pos- 
terior extremity  ;  the  excretory  bladder  is  elongated  and  reaches  to  the 
pharynx  ;  the  genital  pore  lies  laterally  near  posterior  margin  of  ventral 
sucker  ;  no  cirrus  pouch.  The  testes  are  round  or  ramified,  and  lie 
side  by  side  in  the  posterior  half  of  the  body,  the  ovary,  corresponding 
in  form,  lies  in  front  of  one  testis.  The  vitellaria  occupy  the  whole 
of  the  sides  and  almost  reach  the  median  line  on  the  back.  Laurer's 
canal  is  present  ;  there  is  no  receptaculum  seminis  ;  the  uterus,  behind  the 
ventral  sucker,  forms  a  prominence.  The  eggs  are  fairly  large.  The  para- 
sites live  mostly  in  pairs  within  cysts  in  the  lungs  of  mammals. 

Paragonimus  westermani  (Kerb.),  1878. 

vSyn.  :  Distoma  westermani ,  Kerb.,  1878  ;  Distoma  ringeri,  Cobb.,  1880  ; 
Distoma  pulmonale,  Baelz.,  1883  ;  Distoma  pulmonis,  Suga,  1883  ;  Mesogoni- 
mus  westermani,  Raill.,  1890. 

The  body  is  of  a  faint  reddish-brown  colour  a.nd  plump  oval 
shape.  The  ventral  surface  is  a  little  flattened  ;  the  parasite 


PARAGONIMUS    VVESTERMANI 


161 


measures  8--io  mm.  in  length,  4 — 6  mm.  in  breadth  and  diameter. 
The  suckers  are  of  equal  size  (0*75  mm.),  the  oral  sucker  is  sub- 
terminal  ;  the  ventral  sucker  is  placed  somewhat  in  front  of  the 
middle  of  the  body.  The  pharynx  is  small  and  close  behind  the 
oral  sucker  ;  the  oesophagus  is  very  short,  and  the  intestinal  caeca 
present  slight  sinuosities.  The  cuticle  is  provided  with  scale-like 
spines  ;  the  excretory  pore  opens  at  the  posterior  end  rather  on  the 
ventral  surface,  the  elongated  excretory  bladder  gathers  in  branches 
from  all  sides.  The  genital  pore  is  placed  near  the  posterior  margin 
of  the  ventral  sucker  and  a  little  laterally;  next  to  it  on  one  side 
is  the  prominence  of  the  uterus,  and  on  the  other  side  'the  ramified 
ovary;  the  two  ramified  testes  lie  side  by  side  in  the  posterior 
end.  The  ^vitellaria  are  at  the  sides, 
almost  reaching  the  median  line  on  the 
dorsal  surface,  but  only  reaching  the  in- 
testinal branches  on  the  ventral  surface. 
The  eggs  are  oval,  brownish-yellow,  fairly 
thin-shelled,  and  measure  0-0875 — 0-1025, 
mm.  in  length  by  0*0525 — 0-075  mm.  in 
breadth  (average  0-0935:0-0570  mm.) 


i  0 


FIG.  92. — Paragonimus  westermani  (Kerb.)  (natu- 
ral size).  To  the  left,  dorsal  aspect  ;  to  the  right, 
ventral  aspect.  (After  Katsurada.) 

Paragonimus    westermani    was  discovered   by          FIG.  Q^.—Parazonimus   wcs- 
Kerbert  in  a  royal  tiger  that  died  in  Amsterdam  ;      termani  (Kerb.).  Seen  from  the 

the  parasites  were  found— mostly  in  pairs— en-  T^f1  SUxrfaCT?V     Iu/1'1  (After 

.        ,    .  Leuckart.)      Mouth,   pharynx, 

closed   in   superficial    cysts    of    the    lungs.    Soon  intestinal     branches;     at    the 

after,  Balz  observed  the  eggs  of   this   species  in  sides  of  which  the  vitelline  sacs 

the  sputum   of  some  Japanese  who   were   suffer-     are  observed-    The  genital  pore 
,  is  behind    the  ventral   sucker, 

ing  from  haemoptysis,  that  was  of  endemic  and  next  to  it,  at  the  left,  the 
occurrence  in  a  certain  district  of  Japan.  The  ovary  ;  at  the  right,  the  uterus  ; 
observer,  nevertheless,  mistook  them  for  the  the  two  testes  at  the  hack : 
spores  of  gregarines  (Gregarina  pulmonalis  s. 
fused).  The  worm  arising  from  these  ova  was 
first  observed  in  man  by  Ringer  (in  the  bronchi  of  a  native  of  Formosa,  who 
was  likewise  suffering  from  parasitic  haemoptysis).  The  specimens  sent  to 
Manson  and  Cobbold  have  been  described  as  Distoma  ringeri ;  whereas 
Balz,  after  finding  the  species  himself,  gave  it  the  name  of  Dist.  pulmonale. 
Subsequently  the  parasite  has  often  been  observed  in  China,  Korea,  and 
especially  in  Japan,  where,  according  to  Katsurada,  there  are  no  districts 
that  are  entirely  free  from  hepatic  flukes.'  The  mountainous  provinces  of 
II 


the    excretory    vessel    in    the 
middle. 


l62 


THE    ANIMAL    PARASITES   OF  MAN 


Okayama,  Kumamoto,  Nagano  and  Tokushima  are  the  principal  centres. 
[Stiles  has  also  observed  this  species  in  North  America,  and  Naunyn  saw 
a  case  in  Strasburg  in  a  colonist  who  had  lived  in  Mexico  and  California 
for  fifteen  years  (Deutsch.  Med.  Woch.,  1897,  Vereins  Beil.,  No.  20,  p.  146). 
— F.  V.  T.] 

In  addition  to  its  occurrence  in  the  royal  tiger  and  in  man,  Parago- 
nimus  westermani,  according  to  Janson,  has  been  found  in  pigs  ;  according 
to  Railliet  and  Katsurada  in  the  dogs  of  Japan,  and  according  to  Ward 
and  Stiles  it  also  occurs  in  dogs,  cats  and  pigs  in  N.  America. 


FIG.  94.  —  Egg  'of 
Paragonimus  westermani 
(•Kerb.),  from  the  spu- 


The  presence   of   flukes  in  the  lung  is   naturally  not  innocuous 
to    man,   but   the    symptoms   are,   as    a   rule,    so    trifling   that    the 

patients  are  able  to  follow  their  occupations 
and  hardly  ever  consult  a  doctor  concerning 
the  haemoptysis.  The  worms  are  found,  in 
the  case  of  human  beings,  often  singly,  in 
cysts  with  hard  walls  the  size  of  hazel  nuts, 
that  do  not  belong  to  the  actual  tissue  of 
the  lung,  but  to  the  bronchial  tubes  with 
which  they  communicate. 

[This  disease  occurs  principally  in  the 
male  sex,  but  seldom  in  old  men  ;  children 
and  women  are  seldom  affected.  The  man- 
ner of  infection  is  unknown. — F.  V.  T.] 

One  danger  threatens  the  patients,  in   so 

far  as  [i  is  P°ssible  for  lar§e  blood-vessels 
to  be  opened  by  the  disintegration  of  the 

lung  tissue  in  the  vicinity  of  the  cysts,  and  thus  copious  haemor- 
rhage may  be  set  up.  Moreover,  the  flukes  also  appear  to  enter 
the  blood-vessels  and  then  are  carried  about  in  the  body;  at  all 
events  softened  centres  or  tubercle-like  neoplasms  have  sometimes 
been  found  in  the  brain  or  other  organs,  and  have  been  found  to 
contain  the  eggs  of  the  lung  fluke  in  large  numbers.  In  this  posi- 
tion the  worms  appear  to  have  perished  at  some  period  before  the 
examination,  but  it  is  certainly  not  improbable  also  that  the  eggs 
invade  the  circulation  direct  from  the  lung,  and  are  then  conveyed 
to  different  parts  of  the  body. 

[Kanamori  doubts  that  the  ova  found  by  Yamagiva  and  others 
in  the  brain,  liver,  &c.,  have  anything  to  do  with  this  parasite, 
especially  as  they  exhibited  no  lid,  and  believes  they  belong  to 
another  parasite.  He  found  them  in  a  cirrhotic  liver  and  in  an 
adenoma_pf  the  rectum. — F.  V.  T.] 

As  to  the  development,  only  the  following  details  are  known  : 


OPISTHORCHIS    FKLINEUS  163 

That  the  eggs  which  reach  the  open  with  the  sputum  before 
segmentation  develop  in  the  water  into  a  miracidium  ciliated  all 
over,  which  hatches  and  swims  about  freely.  Recently  Stiles  has 
identified  with  the  lung  fluke  a  Distomum  first  found  by  Duncker 
encysted  in  the  muscular  system  of  pigs. 

LITERATURE. 

KERBERT,  C.     Z.  Trem.-Kenntn.     (Zool.  Anzgr.,  1878,  i.,  p.  271.) 

Beitr.  z.  Kenntn.  d.  Trem.     (Arch.  mikr.  Anat.,   1881,  xix.,  p.   519.) 
BAELZ,  E.     Ueb.  paras.  Hsemopt.     (Ctrbl.  f.  med.,  Wiss.,  1880,  p.  721.) 
MANSON,  P.     Dist.  ringeri.     (Med.  Tim.  and  Gaz.,  1881,  ii.,  p.  8  ;    and  1882,  ii.,  p.  42.) 
BAELZ,  E.     Ueb.  einig.  n.  Par.  d.  Mensch.     (Berl.  klin.  Wchschr.,  1883,  p.  234.) 
YAMAGIVA,  K.     Lungendistomenkrkht.  i.  Japan.     (Arch.  f.  path.  An.,  1892,  cxxvii.) 

Z.  Aet.  d.  Jackson' schen  Epilepsie.     (Ibid.,  1890,  cxix.) 
MIURA,  M.     Fibr.  Tuberkel  verurs.  d.  Paras.-Eier.     (Ibid.,  1889,  cxvi.) 
WARD,  H.  B.      Dist.  west.  i.  d.  verein.  Staaten.      (C.  f.  B.  u.  P.   1894,  xiv.,    p.  362, 

and  1895,  xvii.,  p.  304.) 

RAILLIET,  A.     Par  d.  anim.  dom.  du  Japon.     (Le  natural,  1891,  xii.,  p.  143.) 
JANSON.     Mitth.  d.  Ges.  f.  Natur-  u.  Vlkrkde.  Ostas.,  1897,  Nos-  59»  60. 
KATSURUDA,   F.     Beitr.   z.    Kenntn.   d.   Dist.   west.     (Ziegler's  Beitr.   z.   path.   Anat. 
u.  z.  allg.  Path.,  1900,  xxviii.,  p.  506.) 

Gen.  4.  Opisthorchis,  R.  Blanch.,  1845. 

Fasciolidae  of  medium  size,  with  long  flattened  bodies,  usually  attenu- 
ated anteriorly.  The  cuticle  usually  has  no  spines.  The  suckers  are  small 
and  fairly  close  together.  Intestine  with  pharynx,  short  resophagus  and 
long  unramified  intestinal  ca?ca.  The  genital  pore  is  close  in  front  of  the 
ventral  sucker  ;  there  is  no  cirrus  pouch.  The  testes  in  the  posterior  end, 
situated  obliquely  one  behind  the  other,  are  lobulated  or  ramified  ;  the 
ovary  in  front  of  them  lobulated  or  unlobulated  ;  and  behind  it  there 
is  a  large  receptaculum  seminis.  Laurer's  canal  present  ;  vitellaria  at  the 
sides  not  extending  beyond  the  ventral  sucker  towards  the  front.  The 
uterus,  with  oblique  coils,  occupies  the  central  field  in  front  of  the  ovary. 
The  excretory  bladder  is  Y-shaped,  the  long  united  part  running  in  the 
shape  of  an  S  between  the  testes.  The  parasite  lives  in  the  bile  ducts 
of  mammals  and  birds. 

i.     Opisthorchis  felineus,  Riv.,  1885. 

Syn. ;  Distoma  conus,  Gurlt,  1831  (nee  Creplin,  1825);  Dist.  lanceolatum, 
v.  Sicb.,  1836,  v.  Tright,  1889  (nee  Mehlis,  1825  =  Fasciola  lanceolata,  Rud., 
1803);  Dist.  sibiricum,  Winogr.,  1892;  Dist.  tenuicolle,  Muhl.,.  1896. 

This  parasite  is  yellowish-red  in  the  fresh  condition,  and  almost 
transparent.  The  body  is  flat,  with  a  conical  neck  at  the  level 
of  the  ventral  sucker  marked  by  a  shallow  constriction  :  this, 
however,  is  only  noticeable  in  fresh  and  somewhat  contracted 
specimens.  Posteriorly  to  the  ventral  sucker  the  lateral  borders 
run  fairly  parallel  ;  the  posterior  end  is  either  pointed  o>  rounded 
off.  The  length  and  breadth  vary  according  to  the  contraction,  being 


164 


THE    ANIMAL   PARASITES   OF   MAN 


usually  8— ii  mm.  by  1-5—2  mm.  -The  suckers  are  about  i  to  £  of 
the  length  of  the  body  distant  from  each  other,  and  of  about 
equal  size  (0*23 — 0*25  mm.).  The  oesophagus  is  hardly  any  longer 
than  the  pharynx,  which  lies  close  behind  the  oral  sucker ;  the 

intestinal  branches  reach  almost  to  the  poste- 
rior border  and  are  often  filled  with  blood.  The 
excretory  pore  is  at  the  posterior  extremity, 
and  the  excretory  bladder  forks  in  front  of  the 
anterior  testis.  The  testes  in  the  posterior 
fourth  of  the  body  lie  obliquely  one  behind 
the  other  ;  the  anterior  one  has  four  lobes, 
the  posterior  one  five  lobes  ;  the  ovary  is  in 
the  median  line,  stretched  obliquely,  with 
simple  or  slightly  lobate  border  ;  behind  it 
lies  the  large  pear-  or  retort-shaped  re- 
ceptaculum  seminis  and  the  Laurer's  canal. 
The  uterus  is  in  the  median  field.  The 
vitellaria  occupy  the  fairly  broad 
lateral  areas,  in  about  the  central 
third  of  the  body  beginning 
behind  the  ventral  sucker,  and 
terminating  at  about  the  level  of 
the  ovary  ;  the  acini  are  small 
and  arranged  in  groups  of  seven 
to  eight,  separated  by  interstices. 
The  genital  pore  is  close  in  front 
of  the  ventral  sucker.  The  eggs 
are  oval  with  sharply-defined 
operculum  at  the  pointed  pole, 
0^030  :  O'Oii  mm. 

This  species,  which  is  frequently  confused  with  others,1  inhabits  the 
gall  bladder  and  bile  ducts  of  the  domestic  cat  in  particular ;  but  is 
also  found  in  the  dog,  in  the  fox,  and  in  Gulo  borealis.  It  has  been  observed 
in  France,  Holland,  North  Germany  (being  particularly  frequent  in  East 
Prussia),  in  Russia,  Scandinavia,  Siberia,  Japan,  Hungary,  and  Italy.  The 
North  American  form  (from  cats  and  Canis  latrans}  is  a  distinct  species 
(Opisthorchis  pseudo-jelineus}. 

In  man  this  species  was  first  found  by  Winogradoff  in  Tomsk 
(nine  cases),  then  by  Kholodkowsky  in  a  peasant  from  the  neigh- 


s'FIG.  95.— Opisthorchis 
felineus,  Riv.,  from  the 
liver  of  the  domestic  cat. 

IO/I. 


FIG.  96. — 
Egg  of  Opit- 
thorchis  feli- 
neus, Riv. 
830/1. 


1  Braun,  M.,  "  Die  Leberdistomen  der  Haiiskatze  u.  verw.  Arten  "  (C.  /.  B,  u.  P.,  1893, 
xiv.,  p.  381). 


OPISTHORCHIS   FELINEUS 


bourhood  of  St.  Petersburgh  who  had  travelled  a  great  deal  in 
Siberia,  and  finally  by  Askanazy  in  five  persons  who  were  natives 
of  the  East  Prussian  district  of  Heydekrug.  In  Tomsk  Opisthorchis 
felineus  is  the  most  frequent  parasite  of  man  that  comes  under 
observation  at  post  mortem  (6-45  per  cent.),  whereas  Tcenia  saginata 
has  only  been  found  in  3^2  per  cent.,  Echino- 
coccus  in  2*4  per  cent.,  Ascaris  lumbricoides  in  i'6 
per  cent.,  and  Oxyuris  vermicularis  in  o-8  per  cent, 
of  the  autopsies.  In  the  district  of  Heydekrug, 
however,  the  species  in  question  is  also  frequent, 
as  in  a  few  years  five  cases  came  to  our  know- 
ledge (of  which  three  were  diagnosed  by  the  dis- 
covery of  the  eggs  in  the  faeces). 

In  none  of  Winogradoff's  nine 
cases  had  the  death  of  the  patient 
been  caused  direct  by  the  para- 
sites, yet  more  or  less  extensive 
alterations  in  the  liver  were  found 
in  all  of  them  ;  such  as  dilatation  of 
the  bile  ducts  with  inflammation 
and  thickening  of  their  walls,  and 
centres  of  inflammation-  or  atrophy 
in  the  liver  substance  ;  icterus 
was  present  five  times  and  atrophy 
of  the  liver  an  equal  number  of 
times  ;  ascites  was  observed  three 
times,  and  in  two  cases,  probably 
of  recent  date,  the  organ  was  en- 
larged. The  number  of  parasites 
found  fluctuated  between  a  few 
and  several  hundreds. 

In  two  of  Askanazy's  cases, 
which  he  examined  more  closely, 
a  carcinoma  was  revealed  at  the 


FIG.  98. — Opis- 
thorchis felineus, 
Riv.,  from  the 
liver  of  the  domes- 
tic cat.  Extended 
specimen  for  com- 
parison with  D, 
sibiricum. 


FIG.    97.—  Dis- 

tovnurn  sibiricum, 
from  the  liver  of 
man.  (AfterWi- 

post  mortem,   which   had  developed    nogradoff.) 
at    the    pjaces     most    invaded    by 
flukes,  so  that  perhaps  there    may 

be  grounds  for  the  connection  which  the  author  seeks  to  estab- 
lish between  cancer  of  the  liver  and  the  changes  induced  by  the 
parasites  ;  these  changes  consist  of  numerous  and  even  ramified 
proliferations  of  the  epithelium  of  the  biliary  duct  into  the  con- 
nective tissue,  which  is  likewise  proliferated.  The  number  of  worms 


l66  THE    ANIMAL   PARASITES    OF    MAN 

found  in  one  case  amounted  to  over  one  hundred  ;  in  a  second 
case,  in  which  the  parasites  had  also  invaded  the  excretory  duct 
of  the  pancreas,  their  number  was  even  larger. 

Winogradoff  as  well  as  Askanazy  found  isolated  flukes  in  the 
intestine  also. 

Unfortunately,  nothing  much  is  known  of  the  history  of  the 
development  of  Opisthorchis  felineus ;  we  are  only  aware  that  when 
deposited  the  eggs  already  contain  a  ciliated  miracidiurh,  which, 
however,  according  to  my  experience,  does  not  hatch  out  in  water, 
but  only  after  the  introduction  of  the  eggs  into  the  intestine 
of  young  Limnceus  stagnalis  ;  no  further  development,  however, 
occurred.  Winogradoff  states  that  he  has  seen  the  miracidia 
hatch  after  the  eggs  had  been  kept  in  water  for  a  month 
at  37°  C. ;  the  author  has  even  observed  free  miracidia  in  the 
bile  of  a  human  corpse  and  that  of  a  dog  respectively. 

In  one  of  his  nine  cases  Winogradoff  also  saw  a  small 
fluke  beset  all  over  with  spines,  which  he  conjectured  to  be 
the  young  stage  of  Opisthorchis  felineus ;  as,  however,  accord- 
ing to  my  experience,  this  species,  even  in  smaller  specimens,  is 
always  without  spines,  the  above  hypothesis  cannot  be  accepted. 
It  is  much  more  probable  that  one  of  the  other  species  that  also 
invade  the  liver  of  cats  may  incidentally  be  introduced  into  man  ; 
we  know,'  in  fact,  that  Metorchis  albidus  (Braun)  and  Met.  truncatus 
(Rud.)  are  both  covered  with  spines.  As,  however,  the  spines 
of  the  first-named  species  are  fairly  variable  and  the  creatures  also 
possess  a  differently  formed  body  (spatula-shaped),  it  may  be 
assumed  that  probably  Winogradoff  had  found  Metorchis  truncalm 
(Rud.),  1819,  in  his  patient. 


Metorchis  truncatus  (Rud.),  1819. 

The  specimens  of  this  species,  which  attain  a  length  oi  2  mm., 
are  slender  and  skittle-shaped  ;  the  anterior  end  is  pointed  and  the 
posterior  truncated,  and  provided  with  a  tuberosity  that  resembles 
a  terminal  sucker ;  for  this  reason  the  discoverer  of  the  species 
(Rudolphi)  classed  it  with  the  amphistomes.  The  cuticle  in  the 
young,  as  well  as  in  the  adult  specimens,  is  entirely  and  closely 
covered  with  spines.  The  suckers  are  on  an  average  of  equal 
size  (0-134 — 0-172  mm.),  the  ventral  sucker  lies  somewhat  in 
front  of  the  middle  of  the  body.  The  pharynx  is  small  (0*09 
mm.),  the  oesophagus  minute,  the  intestinal  branches  reach  to  the 


METORCHIS   TRUNCATUS 


I67 


posterior  extremity.      Between  them,  and    in  front    of    their  blind 

ends,     lie     the    two     elliptical    testes,    one    generally   a    little     in 

front   of  the   other.     In  front   of  them, 

either   in   the  median  line  or    somewhat 

laterally,    the    spheroid    ovary    is    situ- 

ated ;    in  front,  again,  is  the  uterus,  the 

coils   of  which    usually    extend    beyond 

the    median    field.      The    vitellaria    are 

at   the  sides  of  the  central  third  of  the 

body,   thus  commencing   in  front  of  the 

ventral  sucker  ;  the  cirrus  pouch  is  lack- 

ing ;    the  genital  pore  is  close    in    front 

of  the  acetabulum.      The  excretory  pore 

is   situated    at    the    posterior  extremity. 

Eggs,   0^029  :  O'on  mm. 

This  species  is  known  to  occur  in 
the  seal,  in  the  domestic  cat  and  dog, 
in  the  fox  and  in  Gulo  borealis,  but  it 
easily  escapes  observation  in  conse- 
quence of  its  small  size.  Some  circum- 
stances point  to  the  likelihood  that 

both     this    Species    and  OpisthorchlS    feli- 

neus.  may   invade  their   hosts  by  means 

Of    infected    fish,  but    hitherto  the  experi- 
,    ,    j.      ,.  ,  ,    .         ,  .       ,  . 

mental  feedings  conducted  in  this  direc- 

tion   by    Askanazy    have     not     yielded 

positive   results  ;      in    any   case    it   is   a 

remarkable   circumstance  that,  in  ttye  five  cases  from  East  Prussia, 

specimens    of   Dibothriocephalm  latus   were    also  present,  and   these 

undoubtedly  originate  from  fish.1 


7. 


FIG.    gg.—Metorchis  truncatus, 


Ventral   sucker  ;      /.,   intestinal 
fork;    V.sc.,  vitelline  sacs;     T., 

testes  ;  o.,  ovary  ;  R.S.,  recep- 
taeulum seminis  ;    ut.,  uterus. 


1  Rivolta,  "  Sopra  una  spec,  di  Distoma  nel  gatto  e  nel  cane  "  (Giorn.  anat.,  fisiol. 
e  pat.  d.  anim.,  1884,  xvi.,  p.  20)  ;  Zwaardemaker,  H.,  "  Cirrhos.  paras."  (Arch.  /. 
path.  An.,  1890,  cxx.,  p.  197) ;  Winogradoff,  K.,  "  Ein  neues  Dist.  a.  d.  menschl.  Leber 
(Nachr.  v.  d.  K.  Tomsk'schen  Univ.  [1891]  1892,  iv.,  p.  116)  ;  "Ein  zweit.  Fall  v.  D. 
sib."  (ibid.,  p.  131);  "  Ueb.  Wurmer,  welche  i.  menschl.  Korp.  paras."  (ibid.,  [1892] 
1893,  v.);  Braun,  M.,  "  Ueb.  ein  f.  d.  Mensch  neues  Dist."  (C.  /.  B.  u.  P.,  1894,  xv., 
p.  602);  Ward,  H.  B.,  "On  Dist.  fel.  in  the  Un.  St."  (Veterin.  Magazine^  1895); 
Kholodkovsky,  N.,  "  Sur  quelq.  rar.  par.  de  I'homme  en  Russie  "  (Arch,  paras.,  1898, 
i-,  P-  354^  I  Cholodkovsky,  N.,  Icones  helm.  horn.  II.,  St.  Petersb.,  1898,  plate  xi., 
fi£.  115  ;  Askanazy,  M.,  "  Ueb.  Inf.  d.  Mensch.  mit  Dist.  felin.  in  Ostpreussen  u.  ihren 
Zusammenhang  mit  Leberkrebs  "  (C.  /.  B.,  P.  u.  L,  1900  [i],  xxviii.,  p.  491);  "Dist. 
fel.  beim  Mensch.  i.  Ostpr"  (Verh.  d.  D.  pathol.  Ges.,  1900,  iii.,  p.  72) ;  Kamensky,  G., 
"  Not.  helm.,  i.,  Charkow,  1900;  Braun,  M.,  "  Z.  Kenntn.  d.  Trem.  d.  Sdugeth."  (Zool. 
Jahrb.  Syst.,  1901,  part  xiv.,  p.  314). 


l68  THE   ANIMAL   PARASITES   OF   MAN 

2.     Opisthorchis  sinensis  (Cobb.),  1875. 

Syn.:  Distoma  sinense,  Cobbold,  1875;  Dist.  spathulatum,  R.  Leuck^ 
1876  (nee  Rudolphi,  1819);  Dist.  hepatis  endemicum,  s.  permciosiim,v'~B3.elz, 
1883;  Dist.  hepatis  innocuum,  Baelz,  1883;  Dist.  japonicum,  R.  Blanch., 
1886. 

This  parasite  resembles  Opisthorchis  fcli'neus  in  shape  and  colour, 
though  the  form  may  differ  according  to  the  condition  of  contrac- 
tion and  state  of  preservation ;  the  length  is  10 — 14  mm.,  the 
breadth  2*4 — 3-9  mm.  No  spines.  The  oral  sucker  is  larger  than 
the  ventral  sucker,  and  one  is  about  one-fourth  of  the  length 
of  the  body  distant  from  the  other.  The  testes  are  in  the  pos- 
terior third  of  the  body,  one  behind  the  other,  greatly  ramified 
and  extending  beyond  the  intestinal  bifurcation  ;  the  cucumber-shaped 
receptaculum  seminis  lies  in  front  of  them,  and  in  front  of  the 
receptaculum  seminis  is  the  slightly  lobate  ovary.  The  uterus 
spreads  in  obliquely  directed  convolutions  into  the  central  field 
between  the  ovary  and  ventral  sucker  ;  the  genital  pore  lies  close 
in  front  of  the  ventral  sucker.  The  vitellaria  situated  in  the 
lateral  areas,  commence  more  or  less  near  the  ventral  sucker,  and 
extend  to  the  level  of  the  ovary.  The  eggs  are  oval  with  a 
sharply-defined  operculum  at  the  pointed  pole  ;  they  measure 
0-027 — 0-030  :  0-015 — 0-0175  mm. 

This  parasite  inhabits  the  bile  ducts  and  gall  -  bladder  of 
domestic  dogs  and  cats,  as  well  as  of  human  subjects.  It 
was  discovered  in  man  by  McConnell,  in  Calcutta  (1874),  in  a 
Chinaman  who  died  soon  after  his  admission  to  hospital.  McGregor 
confirmed  eight  more  cases  in  Chinese  in  St.  Louis  (Mauritius), 
and  subsequently  some  Japanese  doctors  and  Baelz  found  the 
worm  in  Japan.  At  the  present  date  the  worm  is  known  to 
occur  in  Tonquin,  China  [and  Japan]  ;  it  has  also  been  found  in 
Hindoos  in  Bengal ;  one  case  also  has  been  observed  in  New 
York  in  a  Chinaman.  Opisthorchis  sinensis  occurs  sporadically 
all  over  Japan,  and  is  endemic  in  certain  districts  of  several  pro- 
vinces of  Hondo  (Central  Japan),  and  in  Kiushu  (South-west 
Island).  The  province  of  Okayama,  in  Central  Japan,  has  a 
specially  evil  reputation  in  this  respect,  for,  according  to  Katsurada, 
there  are  isolated  regions  in  which  it  was  discovered  (by  examina- 
tion of  the  faeces)  that  56  to  67  per  cent,  of  the  population  were 
infected.  The  number  of  worms  that  may  collect  in  a  person  is 
said  to  amount  to  over  4,000  (counted  !),  and  in  about  12  per  cent, 
of  the  cadavers  examined  by  Katsurada  they  were  also  present 


OPISTHORCHIS   SINENSIS 


169 


X.s. 


-  T. 


in    the     pancreas  ;     occasionally    also    the    parasites    were     found 
in  the  intestine,  particularly  in  the  duodenum. 

The  parasites  in   the  liver   produce  alterations  in  the  bile  ducts 
and  in  the  substance   of  the  liver  itself  ;   in  the 
former  case   the   changes   consist   in   local   dilata- 
tions ;  occasionally  also  in  sacculations,  with  pro- 
liferation of  the  connective  tissue  of  the  wall  and 
epithelium  ;    in  the    liver  itself   interstitial   hepa- 
titis      of       varying 
intensity     develops, 
accompanied   by 
atrophy  or  fatty  de- 
generation    of     the  HUUiS!^ 
hepatic     cells  ;   -the 
peritoneal*   covering             v.s. 
and   the   capsule   of 
the    liver    are     also 
affected,  and  in  ad- 
dition  the   mechan- 
ical     functions     are 
interfered   with     by 
the  engorgement   of 
the  bile  ducts.      Af- 
ter   enlargement    of 
the    liver    has    sub- 
sisted for  some  time 
the       organ      com- 
mences   to     shrink. 
In    extensive    infec- 
tion   the    death    of 
the   patient    is    un- 
avoidable (about  14  per  cent,  of  the  sufferers). 

Hitherto,  notwithstanding  all  investigations,  the  mode  of  infec- 
tion has  not  been  discovered  ;  of  the  development  we  only  know 
the  miracidium  stage.  The  eggs,  when  deposited,  already  contain 
a  miracidium  ;  it  is  ciliated  on  all  sides,  but  does  not  leave  the 
shell  spontaneously.1 

1  McCoimeJ],  J.  F.  P.,  "  Rem.  on  the  Anat.  and  Path.  Rel.  of  a  New  Species  of 
Liver-Fluke"  (The  Lancet,  1875,  ii.,  p.  271  ;  and  1878,  i.,  p.  406);  Cobbold,  T.  Sp., 
"The  New  Human  Fluke"  (ibid.,  1875,  ii.,  p.  423);  McGregor,  "A  New  Form  of 
Paralytic  Disease  associated  with  the  Presence] of  a  New  Species  of  Liver  Parasite" 
(ibid.,  1877,  i.,  p.  775);  Baelz,  E.,  "  Ueber  einige  neite  Paras,  d.  Mensch."  (Berl.  klin. 
Wochschr.,  1883,  p.  235);  Ijima,  J.,  "  Dist.  endemicum"  (Journ.  Coll.  Sc.  Imp.  Univ., 
Japan,  1886,  i.,  p.  47);  Moty,  "Lesions  anat.  prod,  par  le  D.  sinense  "  (C.  R.  soc. 
biol.,  Paris,  1893,  p.  224);  Katsurada,  F..  "  Beitr.  z.  Kenntn.  d.  Dist.  spathul."  (Beitr. 
z.  path.  Anat.  u.  z.  all".  Pathol."  [E.  Ziegler],  1900,  xxviii.,  p.  479). 


Ex.bl.  '- 


FIG.  101. — Opisthorchis  sinen- 
sis,  Cobb.  ;  contracted.  About 
6/1.  (After  Katsurada.)  V.s., 
vitelline  sacs  ;  Ex.bl.,  excretory 
bladder  ;  G.p.,  genital  pore  ;  T., 
testes  ;  R.s.,  receptaculum  sem- 
inis,  in  front  of  which  is  the 
ovary. 


FIG.    100.  —  Opts- 
thorch  is    s  i  n  e  n  s  i  s , 
Cobb.,  seen  from  the 
ventral  surface  ;  ex 
tended. 

(After  Leuckart.) 


170 


THE    ANIMAL    PARASITES    OF    MAN 


[In  its  living  state  this  parasite  is  almost  transparent.  The 
eggs  are  brownish  or  black  with  a  thin 
shell.  The  development  of  the  embryo 
proceeds  within  the  worm,  cilia  appearing 
while  the  embryo  is  within  the  parent.— 
F.  V.  T.] 


3.    Opisthorchis  noverca,  nov.  nom. 

Syn.  :  Distoma  confunctum,   Lew.  and    Cunn., 
1872  •   McConnell,  1876  (nee  Cobbold,   1859). 

At    the    autopsy   of    two  •  Mahommedans 
who  died   in  Calcutta,  McConnell  found   a 

large   number    of    Fasciolidae    in    the   thickened    and    dilated    bile 
ducts.     The    worms    were    lancet-shaped,    covered  with  spines,  and 


FIG.  1 02. — Uterine  egg 
and  miracidium  of  Opis- 
thorchis sinensis.  (After 
Leuckart.) 


rh.  _ 


Ms. 


FIG.  103. — Opis- 
thorchis noverca, 
Mihi.  .6/1.  (After 
Leuckart.) 


FIG.  104. — Distomum  conjunctum,  Cobb 
(nee  Lewis  and  Cunn.,  nee  McConnell),  from 
Canis  fulvus.  (After  Cobbold.)  ^..Ven- 
tral sucker  ;  /.,  intestine  ;  Vsc.,  vitelline 
sacs  ;  Ex.,  excretory  bladder  ;  T.,  testes  ; 
O.,  ovary  ;  Ms.,  oral  sucker  ;  Ph.,  pharynx  ; 
UL,  uterus. 


measured  9*5 — 12*7  mm.  in  length  and  2*5  mm.  in  breadth.  The 
two  suckers  were  very  close  to  one  another,  the  anterior  one  being 
larger  than  the  ventral ;  the  genital  pore  opened  immediately  in  front 
of  the  acetabulum  ;  the  pharynx  was  spheroidal  and  the  intestinal 
caeca  extended  far  back.  At  the  commencement  of  the  posterior 


COTYLOGONIMUS  171 

third  of  the  body  were  the  two  testes,  somewhat  apart,  the 
anterior  one  roundish,  the  posterior  one  distinctly  lobate.  The 
oblique  and  slightly  lobate  ovary  was  situated  in  front  of  the 
bifurcation  of  the  Y-shaped  excretory  bladder,  whence  the  uterus, 
in  convolutions  barely  spreading  beyond  the  central  field,  extended 
to  the  pore  ;  the  vitellaria  in  the  lateral  areas  commenced  behind 
the  ventral  sucker  and  extended  to  the  testes.  The  cirrus  pouch 
was  lacking  ;  the  eggs  were  oval,  0*034 — 0*021  mm. 

A  few  years  previously  Lewis  and  Cunningham  found  a  very 
similar  parasite  in  the  liver  of  pariah  dogs,  likewise  in  Calcutta. 
It  may  therefore  be  assumed  that  in  both  cases  the  same  species 
is  dealt  with,  namely,  an  Opisthorchis,  nearly  related  to  Op. 
felineus  and  Op.  sinensis.  The  authors,  however,  connect  their 
discovery  with  a  species  that  Cobbold  found  in  the  liver  of  an 
American  fox  (Canis  fulvus)  that  died  in  London,  and  which 
Cobbold  described  as  Distoma  conjuncium. 

This  name  is  equally  applied  in  literature  to  McConnell's  and  to 

the  Lewis-Cunningham  worm,  although  there  can  be  no  doubt  that 

Dist.  conjunctum,  Cobb.,  is    a  distinct  although  related  species.     As, 

however,  two  different  species  cannot   bear  the  same   name,  I  have 

...given  the  Indian  species  the  name  "  noverca" 

LITERATURE. 

McCoNNELi.,  J.  F.  P.     On  the  Dist.  conj.  as  a  Hum.  Entoz.     (The  Lancet,  1876,  i., 

p.  343  ;  and  1878,  i.,  p.  476.) 
LEWIS,  T.  R.,  and  D.  Cunningham.     Micr.  and  Physiol.  Res.,  XI.  Ann.  Rep.  San.  Com. 

Gov.  India.     Calcutta,  1872,  Append.  C.,  p.  168. 
COBBOLD,  T.  SP.      Syn.  of  the  Distomidae.     (Journ.  Linn.  Soc.,  London,  Zool.,  1859, 

v.,  p.  8.) 

Furth.  Obs.  on  Entozoa  with  Exper.     (Trans.  Linn.  Soc.,   London,   1862,  xxiit., 
p.  349,  plate  33,  figs,  i  and  2.) 


Gen.  6.     Cotylogonimus,  Liihe. 

Small  Fasciolidae,  the  body  of  which  is  divided  into  a  narrow,  movable, 
anterior  part  (neck),  and  a  broader,  less  movable,  posterior  portion,  which 
contains  the  genitaiia.  The  cuticle  closely  beset  with  scale-like  spines. 
The-  suckers  separated  from  one  another  by  a  space  equal  to  half  the 
length  of  the  body  or  more  ;  the  pharynx  is  close  behind  the  oral  sucker  ; 
the  oesophagus  is  long,  the  intestinal  branches  extend  to  the  posterior 
border  ;  the  genital  pore  is  placed  laterally,  and  behind  the  ventral 
sucker.  It  is  surrounded  by  a  muscular  annular  elevation  (genital  promi- 
nence), which  is  provided  with  a  wreath  of  chitinous  rodlets,  shaped  like 
stags'  horns.  There  is  no  cirrus  pouch.  The  testes  are  at  the  posterior  end, 


172 


THE    ANIMAL    PARASITES    OF    MAN 


the  ovary  in  a  median  position  between  them.  Laurer's  canal  with  re- 
ceptaculum seminis  present  ;  the  small  vitellaria  are  at  the  sides  of  the 
posterior  part  of  the  body.  It  lives  in  the  intestine  of  mammals  and 
birds. 

Cotylogonimus  heterophyes  (v.  Sieb.),  1852. 

Syn.  :    Distomum  heterophyes,  v.  Siebold,  1852  ;    Mesogonimus  heterophyes, 
Rail!,,  1890;  Coenogonimus  heterophyes,  Looss,  1900. 

This   parasite   reaches   up   to   2   mm.   in   length   and   i   mm.   in 
breadth ;    the    neck    is    not    sharply    constricted    off ;    in    life    it 

stretches    to    double    the 
length      of      the 

-e.g. 


Ct.g. 


G.c. 


body. 

The  scales  are  rectan- 
gular. O'OO5  -  o-oo6  : 
0*004,  tndr  posterior 
margin  serrate  with  7 
to  9  points.  The  cu- 
ticular  glands  are  nu- 
merous on  the  ventral 
surface,  especially  in  the 
forepart  of  the  body, 
and  partly  discharge  at*., 
the  anterior  border  of 
the  oral  sucker.  The  oral 
sucker  is  cri,  the  ventral 
sucker  035  mm.  in  diam- 
eter ;  the  pharynx  meas- 
ures O'05 — 0-07  mm.  in 
length  ;  the  oesophagus  is 
K's'  about  three  times  as  long  ; 
posteriorly  the  intestinal 
branches  are  directed  one 
towards  the  other  and 
P  ,  .  terminate  next  to  the 

FIG.    105. — Cotylogonimus   heterophyes    (v.  Sieb.) 

53/1.       C.g.,      Cerebral     ganglion  ;      /.,    intestinal  excretory    bladder.      Close 

branches ;    Ct.f>.,   cuticular  glands  ;    V.sc.,  vitelline  •       frrmt    nf    fup    nnstprinr 
sacs  ;    G.C.,  genital  cup  ;    T.,  testes— the  excretory 

bladder  between  them  ;  L.c.,  Laurer's  canal  ;    R.s.,  ends      of      the       intestinal 

receptaculum  seminis,   with  the  ovarium  in  front  i.  i,  ±u 

of  it  ;     Ut.,  uterus  ;    V.s.,  vesicula  seminalis.     On  Drancnes       are  two 

the   left    side    above,    an    egg,  700/1,   is    depicted,  elliptical  testes,  which  are 
and    below    it    three    chitinous    rodlets    from    the  J. 

genitai  cup,  700/1.    (After  Looss.)  not  exactly  on  the  same 

level.     In  the   middle    in 

front  of  them  is  the  receptaculum  seminis,  and  in  front  of  the  latter 
lies  the  spheroidal  or  elliptical  ovarium.      The  two  vasa  efferentia 


T. 


DICROCGELIUM  173 

are  united  to  the  vas  deferens,  which  after  a  short  course  passes  over 
into  the  angularly  bent  seminal  vesicle  ;  after  taking  up  the  prostatic 
glands  it  becomes  united  with  the  metraterm,  and  the  common 
passage  discharges  into  the  genital  cavity.  The  latter  is  some- 
what smaller  than  the  ventral  sucker,  lies  to  the  side  close 
behind  it,  and  carries  a  not  entirely  closed  ring  of  from  75  to 
80  chitinous  rods  (0*02  mm.  in  length).  The  vitellaria  on 
either  side  consist  of  about  fourteen  acini.  The  uterus  is 
spread  almost  throughout  the  entire  posterior  part  of  the  body. 
The  eggs  have  thick  shells  and  measure  0*03  :  0*017  mm.  ;  they 
contain  a  miracidium  ciliated  on  all  sides  and  with  a  rudimentary 
intestinal  sac. 

This  species  was  discovered  in  1851  by  Bilharz  in  the  intestine 
of  a  boy  who  died  in  Cairo  ;  a  second  discovery  was  only 
made  in  1891  and  communicated  by  R.  Blanchard,  so  that  it 
appeared  as  if  the  species  were  very  scarce.  According  to  the 
reports  of  Looss,  this  is,  however,  not  the  case,  but  the  species 
easily  escapes  notice  on  account  of  its  small  size.  Looss  found 
it  in  Alexandria  twice  in  nine  autopsies,  and  once  in  Cairo, 
and  has  recently  stated  that  in  man  "it  is  not  at  all  uncommon 
to  meet  with  the  parasite  in  cadavers,  and  the  eggs  of  the  worm 
in  the  stools  of  the  patients."  The  parasites  occupy  the  central 
third  of  the  small  intestine. 

The  same  species,  according  to  Looss,  frequently  occurs  in 
Egypt  in  dogs,  next  in  cats,  and  has  also  been  found  in  the  fox, 
as  well  as  once  in  Milvus  parasiticus  ;  Janson  also  reports  this 
species  from  the  intestine  of  the  dog  in  Japan. 

LITERATURE. 

SIEBOLD,  C.  TH.  v.     Beitr.  z.  Helm.  hum.     (Z.  f.  w.  Zool.,  1852,  iv.,  p.  52.) 
BLANCHARD,  R.     Note  prel.  sur  le  Dist.  heteroph.     (C.  R.  soc.  biol.,  Paris,  1891  [9], 

iii.,  p.  792.) 
Looss,  A.     Ueb.  d.  Bau  v.  Dist.  fraternum,  n.  sp.  Cassel,  1894. 

Not.  z.  Helm.  Aeg.  I.     (C.  f.  B.,  P.  u.  L,  1896  [i],  xx.,  p.  836.) 

Weit.  Beitr.  z.  Kenntn.  d.  Trem.-Fna.  Aeg.     (Zool.  Jahrb.  Syst.,  1899,  part  xii., 

P-  699-) 

SANDWITH,   F.  M.     Dist.  heteroph.  in  a  living  patient.     (The  Lancet,  1899,  ii.,  No.  14, 
p.  888.) 

Gen.  7.     Dicroccelium,  Dag. 

Medium-sized  Fasciolidae,  with  leaf-shaped  bodies,  pointed  posteriorly 
and  anteriorly.  Cuticle  without  spines  ;  the  suckers  near  each  other  ; 
powerful  ventral  sucker.  Alimentary  canal  with  pharynx,  short  oeso- 
phagus and  long  intestinal  branches,  which  do  not  usually  extend  to 
the  posterior  end.  The  genital  pore  is  usually  close  behind  the  pharynx  ; 


174 


THE   ANIMAL    PARASITES    OF    MAN 


Ms. 


Cb. 


the  cirrus  pouch,  situated  in  front  of  the  ventral  sucker,  contains  the 
vesicula  seminalis.  The  testes  have  either  smooth  or  serrated  borders, 
and  lie  symmetrically  or  obliquely  next  to  or  behind  the  ventral  sucker 

The  ovarium  approaches  the  median  line 
and  is  behind  one  testis.  Laurer's  canal 
and  receptaculum  seminis  are  present.  The 
uterus  lies  behind  the  sexual  glands  and 
spreads  to  the  posterior  border.  The  vi- 
tellaria  in  the  lateral  areas  are  small. 
The  ova  are  mostly  dark  brown  and  nu- 
merous. The  excretory  bladder  is  tubular 
in  form.  The  worm  lives  parasitically  in 
the  liver  and  gall-bladder  (rarely  in  the 
intestine)  of  members  of  all  classes  of  ver- 
tebrate animals — by  preference  in  birds  and 
mammals. 

Dicroccelium  lanceatum,    Stil.  and 
Hass.,  1896. 

Syn.  :  Fasciola  lanceolata,  Rud.,  1803  (nee 
Schrank,  1790)  ;  Distomum  lanceolatum, 
Mehlis,  1825  ;  Dicroccelium  lanceolatum 
Dujardin,  1845. 

The  body  is  pointed  at  both  ends, 
but  is  particularly  narrow  at  the  an- 
terior extremity ;  the  length  of  the 
body  averages  8 — 10  mm.,  the  breadth 
is  from  1*5 — 2*5  mm.,  the  greatest 
breadth  usually  being  behind  the 
middle  of  the  body.  Suckers  distant 
from  each  other  by  about  one-fifth 
the  length  of  the  body ;  the  oral 

FIG.  106. — Dicroccelium  lanceatum,      Sliri,.pr  measures  ahnnt  O'i    the  ventral 
Stil.  and  Hass.      15/1.    V.s.,  Ventral  °  5'  l 

sucker;  Cb.,  pouch  of  cirrus ;  /.,  sucker  about  0'6  mm.  The  pharynx 
"T"^:;  £C^±!  is  globular  and  adjoins  the  oral 
Ms.,  oral  sucker ;  ut.,  uterus.  sucker  ;  the  cesophagus  measures  0*6 

mm.  in  length ;  the  intestinal  branches 

occupy  four-fifths  of  the  body.  The  genital  pore  is  at  the  level  of 
the  bifurcation  of  the  intestine  ;  the  cirrus  pouch  is  small  and 
slender.  The  large,  slightly  lobate  testicles  lie  obliquely  one  at 
the  back  of  the  other  behind  the  ventral  sucker,  and  the  ovarium, 
which  is  considerably  smaller,  is  placed  behind  the  posterior  one  ; 
the  vitellaria,  commencing  at  the  level  of  the  posterior  testicle, 


DICROCCELIUM    LANCEATUM 


175 


terminate  even  before  the  intestines.  The  uterus,  situated  behind 
the  ovarjum,  extends  throughout  the  posterior  end,  not  keeping 
in  the  central  field,  but  spreading  to  the  lateral  areas  with  its 
transverse  coils  ;  at  the  posterior  edge  of  the  body  it  turns  back 
again  and  winds  forwards  to  the  ovarium  in  transverse  loops, 
then  between  the  testes,  and  finally  over  the  back  of  the  ventral 
sucker  to  the  genital  pore,  where  it  terminates.  T-he  thick- 
shelled  eggs  when  young  are  yellowish,  when  older  dark  brown. 
They  measure  0-038 — 0*045  by  0^022 — 0^030  mm.  They  contain  an 
oval  or  more  roundish  miracidium,  the  anterior  part  of  which  is 
ciliated,  and  which  possesses  a  rudimentary  intestinal  sac  with  a 
boring  papilla.  The  miracidia  do  not  hatch  out  in  the  water 
spontaneously,  but,  according  to  Leuckart,  they  hatch  within  the 


FIG.  107.  —  Eggs  of 
Dicrocoelium  lanceaium, 
Stil.  and  Hass.  600/1.  To 
the  left  seen  flat,  to  right 
lying  on  one  side. 


FIG.  1 08.  —  Miracidia  of 
Dicrocoelium  lanceatum.  a., 
from  the  side  ;  b.,  from  the 
dorsum  (after  Leuckart). 


intestine  of  slugs  (Limax,  Arion),  but  they  do  not  increase  either 
in  these  (slugs)  or  in  water-snails. 

The  lancet  fluke  inhabits  the  biliary  duct  of  herbivorous  and 
omnivorous  mammals  (sheep,  ox,  goat,  ass,  horse,  deer,  hare, 
rabbit,  pig),  and  is  often  found  associated  with  the  liver  fluke  ; 
it  is  not,  however,  so  common  nor  so  widely  disseminated,  never- 
theless, it  has  been  met  with  beyond  the  boundaries  of  Europe, 
namely,  in  Algeria,  Egypt,  Siberia,  Turkestan,  and  N.  and  S. 
America. 

In  man  it  is  still  more  uncommon  than  the  liver  fluke  and  has 
hitherto  only  been  observed  seven  times  (Germany,  Bohemia, 
Italy,  France,  and  Egypt)  ;  it  may,  however,  have  occurred  more 
frequently,  and  have  been  overlooked,  as  in  slight  infection  it 
produces  no  special  symptoms. 

The  intermediary  host  is  still  unknown.  Leuckart  for  some  time 
held  the  opinion  that  small  species  of  Planorbis  from  fresh  water, 


176  THE    ANIMAL.  PARASITES    OF    MAN 

which  contain  encysted  fasciolidce,  were  to  blame,  and  he  sup- 
ported his  views  on  a  feeding  experiment  which  seemingly 
yielded  positive  results  ;  this,  however,  is  not  definitely  proved. 
Piana's  statement  that  small  land  snails  are  the  intermediaries  has 
also  not  been  proved. 

LITERATURE. 

JORDENS,  T.  H.     Entom.  u.  Helm.  d.  menschl.  Korpers.  Hof,  1802,  p.  64. 

BREPA,  V.  L.     Mem.  fis.-med.  sopra  i  princip.  vermi  di  corpo.  Rom.,  1811. 

MEHLIS,  C.  F.  L.     Observ.  Anat.  de  Dist.  hep.  et  lane.     Getting,  1825. 

DUBINI,  A.      Entozoograf.  umana.     Milano,    1850. 

PIANA,  G.  P.      Le  cercarie  d.  moll.  stud,  in  rapp.  colla  pres.  del  D.  epat.  e  I),  lane. 

(La  elinica  vet^r.,  1882,  v.) 
ASCHOFF,  L.      Ein  Fall  v.  Dist.  lane.  i.  d.  menschl.  Leber.      (Areh.-f.  path.  An.,   1892, 

cxxx.,  p.  493.) 
ZSCHOKKE,  F.     Selt.  Par.  d.  Mensch.     (C.  i.  B.  u.  P.,  1892,  xii.,  p.  500.) 

Fam.  3.     Schistosomidcz,  Looss. 
Gen.    Schistosomum,    Weinl,    1858. 

Syn.  :    Gyncscophorus,    Dies,     1858  ;    Bilharzia,    Cobb.,    1859  ;     Thecosoma, 
Moq.  Tandon,    1860. 

Digenetic  Trematodes,  that  are  sexually  distinct,  and  with  the  oral  and 
ventral  suckers  in  close  contiguity  ;  the  females  are  filiform  ;  the  males 
have  bodies  that  widen  out  considerably  behind  the  ventral  sucker,  and 
the  lateral  parts  of  which  curl  ventrally,  forming  the  almost  completely 
closed  canalis  gynaecophorus,  within  which  the  female  is  enclosed.  [The 
female  being  longer  than  the  male,  part  usually  protrudes  from  the  posterior 
end  of  the  male. — F.  V.  T.]  There  is  no  pharynx  ;  the  intestinal  branches 
reunite  at  the  posterior  end  of  the  body.  The  genital  orifices  in  both  sexes 
are  in  the  middle  behind  the  ventral  sucker.  There  is  no  cirrus  pouch. 
The  male  has  five  or  six  testes  ;  the  female  one  ovary  ;  the  uterus  is  long. 
There  is  no  Laurer's  canal.  The  ova  are  equally  attenuated  at  either 
extremity  ;  they  have  a  small  terminal  spine,  and  are  not  provided  with 
a  lid.  They  contain  a  miracidium,  ciliated  on  all  sides,  which  is  characterised 
by  the  possession  of  two  large  glandular  cells,  which  discharge  anteriorly 
next  to  the  gastric  sac.  They  live  in  the  vascular  system  of  mammals. 
(An  analogous  species  [Bilharziella]  lives  in  birds.) 

Schistosomum  hcematobium,  Bilharz.,  1852. 
Syn.:  Distoma  htzmatobium,  Bilh. ;  Dist,  capense,  Harley,    1864. 

The  male  is  whitish,  and  measures  12 — 14  mm.  in  length,  but  is 
already  mature  when  4  mm.  long.  The  anterior  end  is  0*6  mm.  or 
a  little  over  in  length.  The  suckers  are  near  each  other,  the  oral 
sucker  is  infundibular,  and  the  dorsal  lip  is  a  little  longer  than 
the  ventral  one.  The  ventral  sucker  is  a  little  larger,  0^28  mm., 
and  is  pedunculated.  A  little  behind  the  ventral  sucker  the  body 


SCHISTOSOMUM    H^MATOBIUM 


177 


broadens  to  a  width  of  i  mm.,  decreasing,  however,  in  thickness  ; 
the  lateral  edges  curl  in  ventrally,  so  that  the  posterior  part  of  the 
body  appears  almost  cylindrical,  0*4 — 0*5  mm.  in  diameter;  the 
posterior  extremity  is  somewhat  more  attenuated.  The  dorsal 
surface  of  the  posterior  part  of  the  body  is  covered  with  spinous 
papillae.  [These  are  used  by 

the    males    to    hold    on    to    the  ^^ 

wall  of  the  veins  during  their 
wanderings.]  There  are  deli- 
cate spines  on  the  suckers  and 
larger  ones  invest  the  entire 
ventral  surface  of  the  gynae- 
cophoric canal,  as  well  as  a 
longitudinal  zone  at  the  edge  of 
that  side  of  the  dorsal  surface 
that  is  covered  by  the  other 
edge  rolling  over  it.  The  oeso- 
phagus is  beset  with  numerous 
glandular  cells  (fig.  in),  and  pre- 
sents two  dilatations  ;  the  intes- 
tinal bifurcation  is  close  in  front 
of  the  ventral  sucker,  the  two 
branches  uniting  sooner  or  later 
behind  the  testes  into  a  median 
trunk,  in  the  course  of  which  it 
may  again  divide  at  short  in- 
tervals. The  excretory  pore  is 
at  the  posterior  end,  but  placed 
somewhat  dorsally ;  the  genital 
pore  is  at  the  beginning  of  the 
gynaecophoric  canal,  thus  behind 
the  ventral  sucker  ;  at  this  spot 


FlG    l09._SchistoSomum 

a     duct      discharges,    which,      to-       Bilh.    12/1.     Male  conducting  the   female 
,',,.,.         ,  ,          .    .          into  the   canalis    gynsecophorus.      (Alter 

wards  the  interior,  broadens  into 


the    seminal    vesicle,    and    then 

continues  into  the  excretory  duct  of  the  four  or  five  testes  (fig.  in). 
The  females  are  filiform,  about  20  mm.  in  length,  pointed  at 
each  end,  and  measuring  0*25  mm.  in  diameter  in  the  middle. 
Their  colour  varies  according  to  the  condition  of  the  contents  of 
the  intestine.  [Posteriorly  they  are  dark  brown  or  blackish.] 
The  cuticle  is  smooth  except  in  the  sucker,  where  there  are 
very  delicate  spines,  and  at  the  tail  end,  where  there  are  other 

T2 


i78 


THE   ANIMAL    PARASITES    OF    MAN 


larger  spines.     The  oral  sucker  is  a  little  larger  than  the  peduncu- 
lated  ventral  sucker  (0*07  and  0*059  mm-  respectively).    The  anterior 

part  of  the  body  measures  from  0*2 
— 0*3  mm.  in  length  ;  the  oesophagus 
is  as  in  the  male.  The  intestinal  bi- 
furcation is  in  front  of  the  ventral 
sucker,  the  'two  branches  uniting  behind 
the  ovarium  and  the  trunk  running  in 
a  zig-zag  manner  to  the  posterior  bor- 
der. There  are  indications  of  blind 
ducts  at  the  flexures.  The  ovary  is 
in  a  median  position.  In  young  females 
it  is  of  an  elongated  oval  shape  ;  in 
older  females  the  posterior  end  becomes 
club-shaped,  whereas  the  anterior  end 
becomes  attenuated  ;  the  oviduct  origi- 
nates at  the  posterior  end,  but  imme- 
diately turns  towards  the  front  and 
joins  the  parallel  vitellaria  in  front 
of  the  ovary  (fig.  112),  where  the 
shell  gland  cells  discharge  ;  the  common 
canal  becomes  dilated  to  form  the  ootype, 
and  then  proceeds  as  the  uterus  along  the 
central  field  to  the  genital  pore,  which  lies 
in  the  middle  line  immediately  behind 
the  ventral  sucker.  The  single  vitelline 
sac  starts  behind  the  ovary  and  ex- 
tends to  the  posterior  end.  The  acini 
are  situated  at  the  side  of  the  excretory 
duct,  which  runs  a  median  course.  The 
eggs  are  fusiform,  much  dilated  in  the 
middle ;  they  have  no  lid,  and  are 
provided  with  a  terminal  spine  (rudi- 
mentary filament)  at  the  posterior  end 
measuring  0*12 — O'lg  mm.  in  length  and 
0-05 — 0-073  mm.  in  breadth  (fig.  113). 
Eggs  retained  in  the  body  of  the  host 
carry  the  thorn-like  appendix  in  the 

vicinity  of  the  posterior  border  but  laterally. 

[The    eggs    are    yellowish    in    colour,    slightly    transparent    and 

provided  with  a  thin  shell.      The  spine  may  sometimes  be  absent. 

The  eggs  apparently  vary  a  great  deal  in  size. — F.  V.  T.] 


FIG.  no. — Transverse  section 
through  a  pair  of  Schistosomum. 
In  the  male  the  point  of  reunion 
of  the  intestinal  forks  has  been 
cut  across.  (After  Leuckart.) 


O.s. 


Oe.  — 


Pi Oe. 


_  V.S, 


Gfp. 


T  r 


FIG.  in. — Anterior  end  of  the 
male  Schistosomum  h&matobium 
(Bilh.).  40/1.  V.s.,  ventral 
sucker  ;  /.,  intestinal  branches; 
G.p.,  genital  pore  ;  T.,  testes  ; 
O.5.,  oral  sucker  ;  Oe.,  oeso- 
phagus with  glandular  cells  ; 
V.s.,  vesicula  seminalis.  (After 
Looss.) 


SCHISTOSOMUM    H.EMATOB1UM 


179 


V.s. 


Schistosomum  hcematobiwm  lives  in  man  in  the  portal  vein  and 
its  branches,  and  thence  is  distributed  to  the  remaining  veins  of 
the  abdomen,  particularly  those  of  the  pelvis  or  the  bladder,  and 
of  the  rectum.  The  worm  is  known  in  Lower 
Egypt  and  Cape  Colony,  and  has  likewise 
been. found  in  Upper  Egypt,  Abyssinia,  Su- 
dan, Mozambique,  Natal  (possibly  it  is  present 
on  the  entire  East  Coast)  ;  it  also  appears  to 
be  found  in  the  interior  of  Africa  ;  in  any 
case  it  has  been  found  on  the  Gold  Coast, 
in  Tunis,  and  in  Algeria ;  beyond  Africa 
it  only  occurs  in  imported  cases,  but  there 
appears  to  be  a  centre  of  infection  in  Arabia 
(Mecca).  It  is  particularly  frequent  in  the 
natives  of  Lower  Egypt,  where  boys  and 
youths  are  especially  attacked. 

[It  has  also  been  observed  in  Angola  in 
the  Congo  State,  in  the  Sahara  region, 
on  the  White  Nile,  near  the  Lake  Albert 
Nyanza  and  in  the  basin  of  the  Zambesi. 
It  has  also  occurred  in  Mauritius,  Syria, 
Bombay,  Penang,  Shanghai,  and  N.  America. 
-F.  V.  T.] 

The  consequences  of  the  infection  are  manifested 
by  catarrh  of  the  bladder,  with  pains  in  the  bladder 
and  in  the  lumbar  region.  At  first  the  urine  is 
still  clear,  later  on  blood  or  purulent  sanguineous 
flakes  appear  at  the  end  of  micturition,  at  the 

commencement     intermittently,     but     later     daily.      mum  hamatobium,     Bilh. 
T,,        ,.  ,,  ,.  £  ,.  .,,          Genitalia   of    the    female 

The  disease  may  thus  continue   for  some  time  with-      (magnified).    V.s.,  ventral 

out    essentially   altering  the  general    condition,  and      sucker  ;       /.,     intestinal 
may  finally   terminate    in  recovery.      If  a    renewed      branches ;    V.d.,  vitelline 

ducts  ;       V.sc.,     vitelline 


FIG.   IT 2.  —  Schistoso- 


or   more,  severe    infection   sets   in,   the   catarrh   be- 


sacs  ;   O.t  ovarium  ;     Oe., 


comes    more     intense,    the     urine     contains    larger      oesophagus  ;      Sh.,    shell 
quantities   of    blood   and   pus,  and    calculi   are   also      glands  ;    U.,  uterus, 
formed.       The    causes     that    have     induced     these 

symptoms  also  attack  the  ureters,  the  pelvis  of  the  kidney,  the  kidneys,  andjthe 
rectum  ;  the  nutrition  suffers  considerably,  and  death  may  set  in  from  uraemia ,. 
pyaemia,  an  intercurrent  pneumonic  process,  or  general  marasmus.  On  section, 
the  wall  of  the  bladder  is  found  to  be  much  thickened,  the  internal  surface  more 
or  less  extensively  covered  with  proliferations  resembling  cock's  combs  or  villi ; 
very  often  the  epithelium  is  missing,  and  ulcerations  also  have  appeared. 
Corresponding  changes  are  also  found  in  the  other  organs,  the  kidneys  are 
affected  with  intense  interstitial  nephritis.  All  these  symptoms  are  caused 
by  the  eggs  of  the  Schistosoma,  deposited  by  the  female,  which  has  pene- 


i8o 


THE  ANIMAL   PARASITES  OF  MAN 


trated  into  the  venous  plexus  of  the  pelvis,  and  which  eggs  reach  the  walls 
of  the  bladder,  &c.,  from  the  blood-vessels.  The  eggs  pass  through  the 
walls  of  the  bladder,  and  are  consequently  easily  found  in  the  urine  of  the 
patients,  mostly  in  the  flakes.  Many  of  the  eggs,  particularly  those  provided 
with  a  lateral  spine,  remain  stationary  in  the  bladder,  irritating  it  still 
further  ;  but  they  finally  perish  and  become  calcified,  the  eggs  remaining  in 
the  lumen  of  the  bladder  are  thus  frequently  the  cause  of  the  bladder 
stones  that  are  so  common  in  bilharziosis.  The  eggs  are  also  swept  into 
other  parts  of  the  body  by  the  circulation,  and  may  thus  be  found  in  all 
the  organs,  though  usually  only  in  small  numbers. 

The  means  by  which  infection  is  brought  about  are  still 
uncertain  ;  we  only  know  that  the  mira- 
cidia  (fig.  113)  enclosed  in  the  evacuated  eggs 
do  not  hatch  if  the  eggs  remain  in  the  urine  ; 
they  perish  with  the  calcified  ova.  As  soon, 
however,  as  the  urine  is  diluted  with  water 
the  shell  splits  open,  generally  bursting  length- 
ways, and  releases  the  miracidium  from  its 
investing  membrane,  so  that  it  can  swim  about 
with  the  aid  of  its  cilia.  In  its  structure  it 
differs  but  little  from  the  miracidium  of  the 
liver  fluke,  as,  for  instance,  in  the  lack  of 
eyes  ;  the  two  large  gland  cells  situated  near 
the  intestinal  sac  are  also  present  in  the  mi- 
racidia  of  the  liver  fluke. 

.The    circumstance    that    this    stage    of   de- 
velopment     already      carries     within     it     the 


bium,  Bilh.,  with  mi-     germs  of    the    future  generation,  indicates  that 

racidium.    which     has  ,        .,,  .        ., 

turned  its  anterior  end     sporocysts  —  and  within  these  cercana  —  must 
towards  the  posterior     ensue  ;  hitherto,  however,  in  spite  of  all  experi- 

6f    the    egg.        275/1.  •i^i.'- ' '•'  v  •  -ill  j- 

(After  Looss.)  ments,  it  has   been  impossible  to  discover  the 

suitable  intermediary  host,  so  that  the  conjec- 
ture may  be  mooted  that  the  sporocyst  stage  is  gone  through  in 
man  himself.  The  experiments  on  monkeys,  however,  conducted 
by  Looss  to  demonstrate  this  had  negative  results.  The  infection 
is  said  to  be  induced  by  drinking  impure  water  from  canals  and 
pits,  and  recently  it  has  been  stated  that  the  miracidia  penetrate 
through  the  skin  of  human  beings  while  they  are  bathing. 

LITERATURE 

BILHARZ,  TH.     Beitr.  z.  Helm.  hum.     (Z.  f.  w.  Zool.,  1852,  ii.,  pp.  453  and  454.) 
CHATIN,   J.     Obs.  sur  le  dev.  et  1'org.  du  proscol.  de  fa  Bilharzia.     (Ann.   Sc.   Nat. 

Zool  ,  1 88 1  [6],  xi.) 
SONSINO,  P.     Ric.  s.  sviluppo  d.  Bilh.     (Giorn.  R.  Ace.    Med.,  Torino,   1889,    xxxii., 

p.  380.) 


SCHISTOSOMDM    JAPONICUM  l8l 

KARTULIS.     Vork.  d.  Eier  v.  Dist.  haem.     (Arch.  f.  path.  An.,  1885,  xc«x.,  p.  139.) 

Weit.  Beitr.  z.  path.  Anat.  d.  Bilh.     (Ibid.,  1898,  clii.,  p.  474.) 
FRITSCH,  G.     Z.  Anat.  d.  Bilh.  haem.     (Arch.  f.  mikr.  An.,  1888,  xxxi.,  p.  192.) 
CHAKER,  M.     Et.  sur  1'hematurie  d'Eg.     These,  Paris,  1890. 
RAILLIET,  A.     Obs.  s.  1'embr.  du  Gynaecoph.  haem.     (Bull.  soc.  zool.,  France,   1892, 

xvii.,  p.  101.) 
Looss,  A.,  Beob.  iib.  Eier  u.  Embr.  v.  Bilh.     (In  Leuckart  :    D.  Paras,  d.  Mensch., 

1894,  2nd  edit.,  i.  5,  p.  521.) 

Bemerk.  z.  Lebensgesch.  d.  Bilh.  haem.     (C.  f.  B.  u.  P.,  1894,  xvi.,  pp.  286  and  340.) 
Rech.  faun.  par.  de  1'Eg.     (Mem.  Inst.  eg.,  1895,  '"•,  P-  1S^>-} 
Z.  An.  u.  Hist.  d.  Bilh.  haem.     (Arch.  f.  Mikr.  An.,  1895,  xlvi.,  p.  i). 
RUTIMEYER,  L.     Ueb.  Bilharziakrkht.     (Mitth.  Klin.  u.  med.   Inst.  d.  Schweiz.,  1894 

[i],  xii.,  p.  871.)     Also  separately. 
LORTET   and   VIALLETON.     Etud.  sur   la   Bilh.  haem.     Paris,   1895.     (Ann.  de  1'univ. 

de  Lyon,   1894,  i*.) 

LAVERAN  and  R.  BLANCHARD.     Les  hematoz:  II.  Vers.  du  sang.     (Bibl.  Med. — Charcot- 
Debove.)     Paris,  1895. 

Schistosomum  japonicum,  Katsurada,  1904. 
Syn. :  Schistosoma  cattoi,  Blanchard,  1905. 

Schistosomum  japonicum  was  discovered  in  1904  by  Professor 
D.  F.  Katsurada,  of  the  Pathological  Institute  of  Okayama.  For 
some  years  the  Japanese  physicians  had  observed  in  the  provinces  of 
Yamauashi,  Hiroshima  (Central  Japan)  and  Saga  (in  Kinshu,  north- 
west island)  an  endemic  disease  characterised  by  enlargement  of  the 
liver  and  spleen,  cachexia  and  ascites.  The  patients  suffered  from 
diarrhoea  (frequently  with  mucous  and  blood-stained  motions), 
anaemia,  occasionally  fever,  and  a  number  died  from  extreme  weak- 
ness. At  the  autopsy  of  such  cases  Yamagiva,  Kurimoto,  Fujinami 
and  others  found  in  several  organs  (more  especially  the  liver) 
numerous  eggs  of  a  hitherto  unknown  helminth. 

In  April,  1904,  Professor  Katsurada  had  the  opportunity  of 
examining  several  cases  of  the  disease,  and  he  noticed  that  the  eggs 
eliminated  with  the  faeces  contained  a  ciliated  embryo  not  unlike  the 
miracidium  of  Schistosomum  hamatobium.  Having  no  opportunity 
of  making  an  autopsy,  he  thought  of  examining  the  dogs  and  cats 
of  the  endemic  areas,  because  he  had  already  found  that  some 
trematodes  of  frequent  occurrence  in  man  are  also  not  infrequently 
present  in  dogs  and  cats.  And  he  had  the  good  fortune  of  at  once 
finding  in  the  portal  system  of  two  cats  from  the  province  of  Yamau- 
ashi numerous  schistosomidae  containing  eggs  exactly  similar  to 
those  previously  found  in  man.  He  published  this  information 
on  August  I3th,  and  named  the  new  trematode  Schistosomum 
japonicum. 

Three  months  later  the  same  parasite  was  found  by  Dr.  John  Catto 
in  sections  of  the  mesocolon  from  a  Chinaman  of  the  province  of  Fukien, 
who  died  of  cholera  at  St.  John's  Island,  Quarantine  Station,  Singa- 
pore. During  life  the  patient  presented  enlargement  of  the  liver  and 


182 


THE  ANIMAL   PARASITES   OF   MAN 


spleen.  At  the  autopsy  the  adipose  tissue  was  found  to  be  remark- 
ably abundant  throughout  the  body.  The  appearance  of  the  peri- 
toneum suggested  repeated  attacks  of  peritonitis.  The  appendices 
epiploicae  were  thickened  and  in  some  places  matted  together.  The 
recto-vesical  pouch  was  almost  obliterated.  The  mesenteric  tissues 
were  all  thickened  and  loaded  with  fat.  The  mesenteric  and  pre- 
vertebral  glands  varied  in  size  from  a  bean  to  a  golf-ball,  the  largest 
forming  a  cluster  near  the  duodenum.  The  liver  was  considerably 
hypertrophied,  its  surface  nodular,  its  consistence  greatly  increased. 
The  coats  of  the  gall  bladder  were  thickened,  and  a  layer  of  fat 
almost  completely  incased  this  organ,  which  was  distended  with 
clear  mucoid  material  containing  several  minute  black  gall-stones. 

The  spleen  was  en- 
larged and  pigmented. 
The  colon  was  much 
thickened  throughout. 
Its  mucous  membrane 
was  swollen,  hyper- 
aemic,  and  friable ;  it 
presented  numerous 
small  circular  super- 
ficial erosions  and 
patches  of  necrosis. 
The  outer  coats  were 
very  tough,  almost  car- 
tilaginous. The  rectum 
was  three-quarters  of 
an  inch  thick  all  round, 
and  was  adherent  to 
the  bladder.  It  nearly 
filled  the  true  pelvis. 
The  sigmoid  flexure  was  uniformly  thickened.  In  tracing  the 
bowel  upwards  the  thickening  became  less  marked  and  more 
patchy.  The  coats  of  the  caecum  and  appendix  vermiformis 
were  uniformly  hypertrophied,  the  mucous  membrane  presenting 
small  patches  of  ulceration  and  necrosis.  The  lower  end  of  the 
ileum  was  thickened  in  patches,  and  the  mucosa  congested  over 
corresponding  areas.  The  liver  and  bowel  cut  gritty  on  section. 
The  bladder  was  thickened  where  adhesions  had  formed  with  the 
rectum,  but  elsewhere  it  was  healthy,  and  nowhere  was  the  vesical 
mucosa  diseased.  The  stomach,  pancreas,  suprarenals,  kidneys,  heart 
and  lungs  showed  no  signs  of  coarse  disease. 

As  the  lesions  above  mentioned  were  peculiar,  some  of  the  viscera 


FIG.   114. — Schistosomum  japonicum. 


SCHISTOSOMUM    JAPONICUM 

were  preserved.  Sections  of  the  liver,  mesenteric  glands  and  bowel 
were  made  in  Singapore  by  Dr.  Finlayson,  and  at  the  Kuala  Lumpur 
Research  Institute  by  Dr.  Daniels.  Numerous  small  oval  bodies 
having  a  smooth  stout  capsule  were  found.  These  bodies  were 
taken  for  Coccidia,  and  the  case  was  published  in  the  Journal 
of  the  Malaya  Branch  of  the  British  Medical  Association  as  a  case 
of  coccidiosis  in  man. 


FIG.  115. — Transverse  section  of  a  mesenteric  vessel,  showing:  (M)two  male  schis- 
tosomes;  (F)  females;  (i)  caeca  in  male;  (L)  caeca  in  female;  (o)  ovum.  Magnifi- 
cation, 56  x . 

On  his  return  to  England  Dr.  Catto  had  the  opportunity  of 
working  out  the  case  at  the  London  School  of  Tropical  Medicine, 
where  systematic  examinations  and  sections  of  all  the  preserved 
tissues  were  made.  Sections  of  the  intestine  showed  the  same  oval 
bodies  and  numerous  small  nematodes  arranged  in  batches  in  the 
mucosa  and  villi  of  the  small  intestine.  The  latter  were  soon  recog- 
nised to  be  the  larvae  of  Tilaria  bancrofti,  and  were  probably  within 


184 


THE    ANIMAL    PARASITES    OF    MAN 


the  lacteals.  The  former  were  supposed  to  be  the  ova  of  some 
hitherto  undescribed  species  of  worm.  The  fact  of  their  having 
been  taken  for  Coccidia  is  not  very  surprising.  Many  times  before 
the  ova  of  worms  have  been  taken  for  Coccidia,  and  conversely 
Coccidia  have  been  mistaken  for  the  ova  of  worms.  In  the  earliest 
recognised  case  of  coccidiosis  in  man  (Gubler's  case),  the  Coccidia 
were  at  first  regarded  as  the  eggs  of  a  trematode.  At  length,  in  the 
smaller  mesenteric  blood-vessels,  Catto  found  male  and  female  speci- 
mens of  a  new  species  of  trematode  belonging  jto  ^the  genus  Schisto- 
soma, and  noticed  that  the  ova  within  the  uterus  of  the  female  worm 
corresponded  in  every  way  with  the  oval  bodies  J:ound  in  the  various 

organs.  In  the  bowel 
of  this  case  were  also 
found  specimens  of  the 
more  common  parasitic 
worms  —  Tricocephalus 
trichurius,  Uncinaria 
duodenalis  and  A  scar  is 
htmbrico'ides  —  together 
with  their  respective 
eggs.  It  was  clear, 
however,  that  the  ana- 
tomical lesions  afore- 
mentioned were  due  to 
the  trematode  parasite. 
Specimens  of  the 
trematode  were  sent  to 
Professor  Blanchard, 
who  recognised  that 
they  belonged  to  a  new 
species  which  he  named 
Schistosoma  cattoi. 
After  the  publication  of  his  paper  Dr.  Catto  received  a  section  of 
intestine  prepared  in  Japan  in  1900,  which  showed  ova  having  exactly 
the  same  characters  and  occupying  the  same  position  in  the  intestine 
as  in  his  own  case. 

Morphologically,  Schistosoma  japonicum  is  "tibt  unlike  the  well- 
known  S.  hcematobium  discovered  by  Bilharz  in  1851.  The  dis- 
tinctive characteristics  of  the  new  trematode  are  its  smaller  dimen- 
sions ;  the  larger  size  of  its  acetabulum  or  posterior  sucker  as 
compared  with  the  anterior  sucker  ;  the  .smooth,  non-tuberculated 
integument  of  the  male ;  the  smaller,  non-spined  ova  contained  in 


FIG.  116. — Section  of  appendix  (stained),  showing 
ova  in  masses,  a  dense  submucous  layer,  and  a  less 
marked  subperitoneal  layer. 


SCHISTOSOMUM   JAPONICUM 


the  female.  A  comparative  study  of  the  anatomy  of  the  two  Schisto- 
somidae  will  probably  show  other  morphological  differences.  Dr. 
Catto  mentions  a  larger  vas  deferens  and  lobular  testicles  in  the 
male,  and  a  different  arrangement  of  the  yolk  cells  in  the  female. 

The  dimensions  given  by  Dr.  Catto  refer  to  a  few  spirit  specimens, 
and  are,  therefore,  only  relative.  The  male  measures  9  mm.  in  length 
by  less  than  \  mm.  in  breadth.  The  slender,  almost  cylindrical,  female- 
is  longer  than  the  male  and  measures  0-113  mm.  in  diameter.  The 
eggs  are  of  a  yellowish-brown  colour,  they  are  oval,  have  neither 
operculum  nor  spine,  and  measure  from  60  to  90  yu  in  length  by 
30  to  50  yit  in  breadth. 

Professor  Katsu- 
rada's  measurements 
refer  to  fresh  speci- 
mens from  the  cat. 
He  measured  eight 
males,  and  found 
'I0'43  mm.  to  be  the 
average  length.  The 
longest  male  speci- 
men measured  12 
mm.  The  greatest 
breadth  of  this  speci- 
men a  little  behind 
the  centre  of  the 
body  was  '53  mm. 
Only  a  few  females 
were  found  intact ; 
they  measured  from 
8  to  12  mm.  The 
greatest  breadth  of 
the  female  was  '4  mm. 

The  adult  worms  are  found  in  the  smaller  mesenteric  blood- 
vessels. Dr.  Catto  was  unable  to  determine  whether  they  occupy 
the  arteries  or  the  veins,  but  believes  they  occur  in  both.  However, 
the  smooth,  non-tuberculated  skin  of  Schistosomum  japonicum  would 
suggest  a  different  anatomical  habitat  to  that  of  Schistosomum  hcema- 
tobium,  the  integument  of  which  is  beset  with  numerous  spine- 
bearing  protuberances.  Schistosomum  hcematobium  inhabits  the  venous 
system,  and  its  rough  integument  obviously  enables  it  to  adhere  to 
the  inner  coat  of  the  venule  during  oviposition,  and  thus  prevents 
its  being  carried  away  by  the  ascending  blood-stream.  If  Schisto- 


FIG.  117. — Magnified  view  of  fig.  116,  showing  ova. 


l86  THE   ANIMAL    PARASITES    OF   MAN 

somum  japonicum  inhabits  the  arteries,  the  absence  of  integumental 
protuberances  might  be  easily  explained  by  the  fact  that  the 
arterial  current  would  maintain  it  in  its  proper  position. 

In  Catto's  case  the  ova  of  the  parasite  were  found  chiefly  in  the 
intestinal  tract  and  its  appendages.  In  the  intestine,  from  caecum 
to  anus,  the  ova  occupied  roughly  two  concentric  layers,  the  one 
subperitoneal,  where  the  ova  were  comparatively  scarce,  the  other 
in  the  submucous  coat,  where  they  were  innumerable.  Between 
these  zones  in  the  muscular  layers  there  were  single  or  double  rows 
of  eggs  lying  with  their  long  axes  at  right  angles  to  the  bowel.  In 
the  mucosa  they  were  also  plentiful,  especially  in  the  necrotic  areas. 
Of  the  intestinal  tract,  the  rectum  and  appendix  were  most  affected. 
Everywhere  throughout  the  small  intestine  ova  were  found,  but  only 
in  patches  and  in  relatively  small  numbers.  In  the  liver  the  ova 
were  plentiful,  lying  singly  or  in  clusters  embedded  in  the  markedly 
hypertrophied  fibrous  connective  tissue.  They  were  also  found  in 
many  of  the  enlarged  mesenteric  lymphatic  glands,  in  the  outer  wall 
of  the  gall-bladder,  in  the  pancreas,  in  the  liver  capsule,  and  in  the 
fibrous  coat  of  the  larger  mesenteric  vessels.  The  eggs  were  not  in 
the  capillaries — which  they  are  too  large  to  enter — but  in  the  peri- 
vascular  tissue.  Probably  the  female  schist osoma  has  a  means  of 
extruding  them  through  the  walls  of  the  blood-vessel.  Their  further 
distribution  is  probably  due  to  the  lymph  stream.  Where  ova  accu- 
mulate they  provoke  a  small-celled  infiltration,  which  gives  place 
later  to  a.  great  proliferation  of  fibrous  tissue. 

Nothing  is  known  of  the  life  history  of  this  schistosoma.  The 
ova  contain  a  ciliated  embryo,  which  may  develop  in  the  faeces  even 
before  they  are  evacuated.  The  geographical  distribution  of  Schisto- 
somum  japonicum  is  probably  a  wide  one,  and  Dr.  Catto  suggests 
that  the  parasite  was  not  recognised  before  because  its  ova  in  the 
stools  were  mistaken  for  the  ova  of  Uncinaria  duodenalis,  which 
they  resemble  in  size,  shape  and  general  appearance. — [L.  W.  S.] 

Class  II.     Cestodes,  Rud.,  1808. 

Tapeworms  have  been  known  from  ancient  times — at  all  events,  the 
large  species  inhabiting  the  intestines  of  man — and  there  has  never  been 
a  doubt  as  to  their  animal  nature.  The  large  cysticerci  of  the  domestic 
animals  (occasionally  of  man  also)  have  been  known  for  an  equally 
long  period,  but  they  were  generally  regarded  as  excrescences,  or 
hydatids,  until  almost  simultaneously  Redi  in  Italy,  and  Hartmann 
and  Wepfer  in  Germany,  concluded  from  their  movements  and  organisation 
that  they  were  of  animal  nature.  From  that  time  the  cysticerci  have 


CESTODES  187 

been  included  amongst  the  other  intestinal  worms,  and  Zeder  (1800) 
established  a  special  group  (cystici)  for  them.  Things  remained  in  this 
condition  until  the  middle  of  the  last  century,  when  Kuchenmeister, 
by  means  of  his  successful  feeding  experiments,  demonstrated  that  the 
cysticerci  were  definite  stages  of  development  of  certain  tapeworms. 
Before  Kuchenmeister,  E.  Blanchard,  van  Beneden,  and  v.  Siebold  had 
held  the  same  opinion  in  regard  to  other  asexual  cestodes. 

Since  the  most  remote  period  another  question  had  occupied  the  naturalists 
again  and  again,  the  question  of  the  morphological  nature,  that  of  the 
INDIVIDUALITY  OF  THE  TAPEWORM.  The  ancients,  who  were  well  acquainted 
with  the  proglottides  that  are  frequently  evacuated  (Vermes  cucurbitani\  were 
of  opinion  that  the  tape-worm  originated  through  the  union  of  these  separate 
proglottides,  and  this  view  was  maintained  until  the  end  of  the  seventeenth 
century.  In  1683  Tyson  discovered  the  head  with  the  double  crown  of 
hooks  in  a  large  tape-worm  of  the  dog  ;  Redi  (1684)  was  also  acquainted 
with  the  head  and  the  suckers  of  several  Taeniae,  and  Andry  (1700)  found 
the  head  of  Tcenia  saginata,  Bonnet  (1777),  and  Gleichen  Rusworm  (1779) 
found  the  head  of  Dibothriocephalus  latus.  Consequently  most  authors,  on 
the  ground  of  this  discovery,  considered  the  tapeworm  as  a  single  animal, 
that  maintains  its  hold  in  the  intestine  by  means  of '  the  head,  and  like- 
wise feeds  itself  through  it.  The  fact  was  recognised  that  there  were 
longitudinal  canals  running  through  the  entire  length 'of  the  worm,  and  it 
was  thought  that  these  originated  in  the  suckers  ;  and  naturalists  regarded  the 
entire  apparatus  as  an  intestine.  As  it  was  found,  moreover,  that  the  joints 
form  at  the  neck,  and  are^cast  off  from  the  opposite  extremity,  the  tape- 
worm was  also  compared  with  the  polyps,  which  were  formerly  regarded 
as  independent  beings. 

Steenstrup,  in  his  celebrated  work  on  the  alternation  of  generations 
(1841),  was  the  first  to  inaugurate  another  stage  of  advance.  His  studies 
were  followed  still  further  by  van  Beneden,  v.  Siebold  and  Leuckart,  and 
until  a  few  years  ago  all  authorities  adopted  his  views.  Accordingly,  the 
tapeworm  is  composed  of  numerous  individuals,  something  like  a  polyp 
stem,  and,  in  addition  to  the  proglottides — the  sexual  individuals  which  are 
usually  present  in  large  numbers — there  is  ONE  individual  of  different  struc- 
ture, the  Scolex,  which  not  only  fastens  the  entire  colony  to  the  intestine, 
but  actually  produces  this  colony  from  itself,  and  therefore  is  present 
earlier  than  the  proglottides.  The  scolex  is  'a  nurse  which,  though  itself 
produced,  by  sexual  means,  increases  asexually  like  a  Scyphistoma  polyp  ; 
the  tapeworm  chain  has,  therefore,  been  termed  a  Strobila.  Consequently 
the  development  of  the  tapeworms  was  explained  by  an  alternation  of  genera- 
tions. In  support  of  this  opinion  it  was  demonstrated  not  only  that  the 
adult  sexual  creatures,  the  proglottides,  can  separate  from  the  colony  and  live 
independently  for  a  time,  but  that  in  certain  TaBniae,  and  especially  in  many 
cestodes  of  the  shark,  the  proglottides  detach  themselves  long  before  they  have 
attained  their  ultimate  size,  and  thus  separated  continue  to  develop,  grow  and 
finally  multiply  ;  the  scolex  also  exhibits'"  a  certain  independence  in  so  far  as, 
though  not,  as  a  rule,  capable  of  a  free  life,  yet  in  some  cases  lives  as  a  free  being, 
partly  on  the  surface  of  the  body  of  marine  fishes  and  partly  in  the  sea.  With  the 
more  intimate  knowledge  of  the  development  of  the  cysticerci,  the  independent 
nature  of  the  scolex  was  recognised.  It  is  formed  by  an  invagination  of  the 


l88  THE    ANIMAL    PARASITES    OF    MAN 

cyst  developing  from  the  oncosphere,  in  some  cases  (Ccenurus}  in  large 
numbers,  in  other  cases  (Echinococcus}  only  after  the  parent  cyst  has 
developed  several  daughter  cysts.  Released  from  its  cyst  and  placed  in 
suitable  conditions,  it  goes  on  living,  and  increases  at  its  posterior  end  by 
proliferation.  In  these  cases  a  double  change  of  generations  must  be 
accepted  (ONCOSPH^RA — mother  cyst  ;  SCOLEX,  one  or  several  in  number — 

PROGLOTTIDES). 

The  view  that  the  tapeworm  consists  of  a  colony  originating  from  dimor- 
phous individuals,  and  that  its  development  takes  place  through  an  alternation 
of  generations,  has  been  recently  assailed  by  several  authors.  The  cause  for 
this  disagreement  was  furnished  partly  by  changes  in  the  views  concerning  the 
alternation  of  generations  itself,  partly  by  those  cestodes  which  exhibit 
no  external  segmentation,  as  Ligula,  in  which  the  genitalia  only  are 
repeated  again  and  again,  and  partly  by  the  so-called  one-jointed  cestodes 
(Amphilina,  Caryophyll&us,  Gyrocotyle,  &c.),  the  genitalia  of  which  only 
appear  once  in  each  specimen.  Without  arguing  the  pros  and  cons  of 
the  opposing  views,  we  must  nevertheless  remark  that  even  though  the 
single-jointed  cestodes  must  be  considered  the  most  primitive  tape-worms, 
it  does  not  follow  that  the  proglottides  are  merely  segments  of  the  body. 
The  advancement  o'f  a  "  morphologically  strictly  limited  subordinate  stage 
of  individuality  "  in  itself  essentially  concedes  the  individuality  of  the 
proglottides.  If,  on  the  other  hand,  the  appearance  of  numerous  little 
heads  in  Ccenurus  and  Echinococcus  is  regarded  as  a  multiplicate,  there 
is  no  reason  why  the  formation  of  only  ONE  head  in  Cysticercus  should  be 
anything  else  ;  the  NUMBER  of  the  offspring^  is  of  no  importance.  A 
difficulty  is  certainly  presented  by  such  forms  as  Ligula,  but  one  can  in 
these  either  take  it  for  granted  that  the  formation  of  the  proglottis  has  not 
yet  set  in  or  that  it  has  already  disappeared.  In  the  former  case  a  lower 
development  of  the  single  individual  must  be  present,  a  view  that  can  hardly 
be  opposed,  as  in  other  creatures  forming  colonies  we  know  that  there  may  be 
a  reduction  of  one  or  numerous  individuals  until  only  the  stage  of  one  organ 
is  left. 

If  we  except  the  tapeworms  with  only  one  proglottis,  the 
Cestodaria,  we  can  always  distinguish  in  the  cestodes  in  the  narrowest 
sense,  one  scolex  and  a  large  or  small  number  of  segments  (pro- 
glottides). The  SCOLEX  serves  the  entire  tapeworm  by  fastening  it  to 
the  internal  surface  of  the  intestinal  wall,  and  therefore  carries  at 
its  end  various  organs  which  assist  in  this  function,  and  which 
are  as  follows  :  (i)  SUCTORIAL  ORGANS,  i.e.,  the  four  round  suckers 
(acetabula),  which  are  placed  cross-wise  at  the  circumference  of 
the  thickened  end  of  the  scolex  ;  further,  the  double  or  quadruple 
groove-like  suckers  (bothridia)  which  are  diversely  shaped  according 
to  the  genera  and  families.1  (2)  CLINGING  ORGANS  (booklets)  that 


1  They  may  remain  simple,  and  are  then  not  separated  from  the  remaining 
muscles  of  the  scolex  ;  or  they  rise  as  roundish  or  elongated  formations  over 
the  scolex,  hollow  on  their  free  surface,  and  are  often  divided  into  numerous 
areas  by  muscular  transverse  ribs.  They  may  also  carry  accessory  suckers  on 
their  surface. 


CESTODES  189 

likewise  appear  in  varying  numbers  and  different  positions,  they 
may  be  on  the  suctorial  organs  or  above  them  on  the  apex 
of  the  scolex  ;  for  instance,  in  many  of  the  Taeniadae  they  appear 
in  a  circle  around  a  single  protractile  organ,  the  rostellum,  or 
the  latter  may  be  rudimentary,  and  is  then  replaced  by  a 
terminal  sucker.  (3)  ROSTRUM.  One  family  of  the  cestodes,  the 
Rhynchobothriidia  carries  four  rostra,  moved  by  their  own  muscular 
apparatus,  on  the  scolex,  and  they  are  beset  with  the  most  diverse 
hooks.  (4)  TENTACLE-LIKE  formations  are  only  known  in  one  genus 
(Polypocephalus). 

The  thickened  part  of  the  scolex  that  carries  the  suckers  is 
usually  called  the  head  ;  the  following  flat  part  connecting  it  with 
the  proglottides  is  called  the  neck,  and  is  sometimes  quite  small. 
In  a  few  cases  the  entire  scolex  (or  head)  disappears,  and  its 
function  is  then  undertaken  by  the  contiguous  portion  of  the  chain  of 
proglottides  which  is  transformed  into  the  so-called  PSEUDOSCOLEX. 

The  proglottides  are  joined  to  the  scolex  in  a  longitudinal  row, 
and  are  arranged  according  to  age  in  such  a  manner  that  the 
oldest  proglottis  is  furthest  from  the  scolex, '  and  the  youngest 
nearest  the  neck. 

The  number  of  segments  varies  according  to  the  species,  from 
only  a  few  to  several  thousands  ;  they  are  either  quadrangular  or 
rectangular  ;  in  the  latter  case  their  longitudinal  axis  falls  either 
longitudinally  or  perpendicularly  to  that  of  the  entire  chain  ; 
when  the  number  of  segments  is  very  large,  the  youngest 
ones  are,  as  a  rule,  transversely  oblong,  the  middle  ones  are 
squarish,  and  the  mature  ones  longitudinally  oblong.  The 
posterior  border  of  the  segments,  as  a  rule,  carries  a  longitudinal 
groove  for  the  reception  of  the  shorter  anterior  border  of  the 
following  proglottis.  The  two  lateral  borders  of  the  segment  are 
rectilinear,  but  converge  more  or  less  towards  the  front,  or  they 
are  bent  outwards.  In  most  of  the  cestodes  the  segments,  even 
starting  at  the  neck,  are  very  flat ;  in  rare  cases  their  transverse 
diameter  is  equal  to  their  dorso-ventral  diameter.  As  a  rule  the 
segments,  singly,  or  several  united  together,  detach  themselves  from 
the  posterior  end,  in  many  cases  only  after  complete  maturity  is 
attained,  and  in  others  much  earlier ;  they  then  continue  to  live 
near  their  parent  colony  in  the  same  intestine  and  continue  their 
development.  Even  when  evacuated  from  the  intestine  the  pro- 
glottides under  favourable  circumstances  can  continue  to  live  and 
creep  about  until  they  perish,  sooner  or  later. 

The    first    proglottis    formed,    and    which    in    a    complete    tape- 


19°  THE    ANIMAL    PARASITES    OF    MAN 

worm  [i.e.,  sexually  complete]  lies  at  the  posterior  end,  is  as  a 
rule  of  smaller  size  and  different  shape,  it  also  frequently  remains 
sterile,  as  likewise  happens  in  the  next  younger  segments  in  a  few 
species  ;  otherwise,  however,  sooner  or  later  the  generative  organs 
develop  in  all  the  segments,  mostly  singly,  sometimes  in  pairs ; 
in  the  latter  case  they  may  be  quite  distinct  from  each  other 
or  possess  some  parts  in  common.  Most  of  the  species  combine 
male  and  female  genitalia  in  the  same  segment,  only  a  few  are 
sexually  distinct  (Dicecocestus).  In  the  hermaphrodite  species  one 
male  and  one  female  sexual  orifices  are  always  present,  and,  in 
addition,  there  may  be  a  second  female  orifice,  the  mouth  of  the 
uterus ;  as  a  rule,  however,  this  is  lacking,  and  in  one  genus  the 
other  sexual  orifice,  the  opening  of  the  vagina,  is  also  absent.  The 
position  of  these  orifices  varies  ;  the  cirrus  and  vagina  usually 
open  into  a  common  space  on  one  lateral  border  or  on  a  surface 
of  the  segments  ;  the  orifice  of  the  uterus  may  be  on  the  same 
surface  or  on  the  opposite  one. 

The  surface  on  which  the  uterus  opens  is  termed  the  VENTRAL 
SURFACE  ;  if  this  orifice  is  absent,  one  must  depend  on  the  female 
organs,  particularly  the  ovary,  which  almost  always  approaches  one 
of  the  two  surfaces ;  the  proximal  surface  is  then  called  the  ventral. 

The  length  of  the  Cestodes — independently  of  their  age — depends 
on  the  number  and  size  of  the  segments,  as  well  as  on  their 
contraction  ;  the  smallest  species  (Davainea  proglottina)  may  measure 
o\5 — i'o  mm.  in  length  ;  the  largest  may  attain  a  length  of  10  mj6., 
and  even  more. 

ANATOMY  OF  THE  CESTODES. 

'  The  entire  superficial  surface  of  the  tapeworms  is  covered  with 
a  fairly  resistant  and  elastic  cuticle,  which  also  covers  the  suckers, 
and  is  reflected  inwardly  at  the  sexual  orifices  ;  in  some  species 
fine  hairs  appear,  either  on  the  entire  body  or  only  in  the  region 
of  the  neck,  on  the  external  surface  of  the  cuticle,  which  exhibits 
several  indistinct  layers.  Close  under  the  cuticle  lies  the  external 
layer  of  the  parenchyma  (basal  membrane)  and  immediately  after 
the  elements  of  the  dermo-muscular  tube.  The  matrix  cells  of  the 
cuticle  are,  as  in  the  Trematodes,  only  on  the  other  side  of  the  peri- 
pheral muscles  in  the  external  zone  of  the  parenchyma  ;  they  are 
fusiform  cells  forming  one  or  two  layers,  but  are  not  arranged  in 
the  manner  of  epithelial  cells.  They  have  fine  branching  pro- 
cesses which  run  between  the  cuticular  muscles,  pass  through  the 


ANATOMY   OF   THE    CESTODES 


Cu. 


basal  membrane  and  penetrate  the  internal  surface  of  the  cuticle 
with  small  pistil-like  enlargements  ;  at  the  internal  surface  of  the 
cuticle  they  spread  out  into  a  thin  layer  (fig.  118.) 

In  addition  to  the  above- 
mentioned,  there  are  other 
cuticular  formations  occur- 
ring on  the  cuticle  of  some 
cestodes,  such  as  immotile 
little  hairs  and  variously 
formed  hooks,  such  as  are 
seen  principally  on  the  scolex. 
Their  development  is  only 
roughly  known  in  a  few 
species ;  they  are  usually 
already  present  in  the  cysti- 
cercus  stage,  and  in  the  same 
order  and  form  as  they  are 
found  in  the  fully-developed 
tape-worms  ;  systematically 
this  is  of  importance,  be- 
cause by  these  structures 
cysticerci  can  be  recognised 
as  belonging  to  certain 
species  of  tape- worms. 

The      CUTICULAR      GLANDS 

in  cestodes   are  scarce. 

The  parenchyma  forms  the 
chief  tissue  of  the  entire 
body,  and  in  all  essentials 
its  structure  is  similar  to 
that  of  the  Trematodes. 

In  the,  parenchyma  of  al- 
most all  the  Cestodes  there 
is  found  in  adult  specimens, 
as  well  as  in  cysticerci,  light 
refracting  concentrically  stri- 
ated structures,  of  a  spher- 
ical or  broad  elliptical 
shape,  which,  on  account 
of  their  containing  carbo- 
nate of  lime,  are  termed  CALCAREOUS  BODIES  (fig.  118,  C.).  Their 
size  varies  according  to  the  species  between  0*003  and  0-030  mm.  ; 


F.V.S. 


L.m 


FIG.  118. — Schematic  representation  of  a 
small  part  of  a  transverse  section  of  Ligula. 
500/1.  (After  Blochmann.)  Bs.,  Basal  mem- 
brane ;  Cu.,  cuticle;  at  its  base  are  the  ter- 
minal laminae  of  the  sub-cuticular  (epithelial) 
cells  ;  in  the  centre  there  is  a  cuticular  organ 
of  sense;  F.v.s.,  follicle  of  vitelline '  sac  ;  Exc. 
excretory  vessel  ;  C.,  calcareous  body  ;  L.m. 
longitudinal  muscles ;  M.c.,  cell  of  muscular 
formation  ;  P,m.,  parenchymatous  or  dorso- 
ventral  muscles ;  PL,  plexus  of  nerve-fibres  ; 
A.m.,  annular  muscles  ;  Sc.c.,  sub-cuticulat 
cell  ;  O.s.,  organ  of  sense  ;  T.c.,  terminal  cell. 


192 


THE    ANIMAL    PARASITES    OF    MAN 


their  frequency  and  position  in  the  parenchyma  also  varies,  but 
they  are  chiefly  found  in  the  cortical  layer.  They  are  the  product  of 
certain  parenchymatous  cells,  in  the  interior  of  which  they  lie  like 
a  fat  globule  in  an  adipose  cell. 

The  MUSCULAR  SYSTEM  of  the  proglottides  is  composed  of  bundles 
of  fibres  which  lie  immediately  below  the  basal  membrane,  of 
dorso-ventral  fibres,  and  of  muscle  plates  that  are  embedded  more 
deeply  in  the  parenchyma.  The  sub-cuticular  muscles  (figs.  118 
and  119)  as  a  rule  consist  of  a  layer  of  circular  muscles  and  of 
longitudinal  muscles,  which  are  frequently  also  represented  by  only 
one  layer  of  fibres  ;  in  other  cases,  however,  the  longitudinal  fibres 
extend  to  between  and  even  beyond  the  matrix  cells.  The  dorso- 


Ex.v. 


Cu. 


•      L.m. 


i^Si^^ 


L.m. 


Sc.c. 


-  Sc.c 
L.m. 


Tr.m. 
T. 


r¥*',t*V££tr>- 


M.f. 


s****ss::::^^ 


5m./. 


FIG.  119.  —  Half  of  a  transverse  section  through  a  proglottis  of  T&nia  crassi- 
collis.  44/1.  Cu.,  cuticle  ;  Ex.v.,  exterior  excretory  vessel,  to  the  right  of 
which  there  is  the  smaller  internal  one  ;  T.,  testicular  vesicles  ;  L.m.,  longitudinal 
muscles  (outside  and  inside)  ;  M.f.,  lateral  medullary  fascicula  with  the  two  accom- 
panying fascicula;  Sc.c.,  sub-cuticular  cells;  5m./.,  submedian  fascicula;  Tr.m., 
transverse  muscles  ;  Ut.,  the  uterus,  and  represents  the  middle  of  the  entire 
transverse  section. 

ventral  fibres  extend  singly  from  one  surface  to  the  other,  and  at 
both  ends  open  out  in  a  brush-like  manner,  and  insert  themselves 
in  the  basal  membrane.  The  deeper  muscles  consist  of  a  peri- 
pheral layer  of  longitudinal  fibres,  which  are  either  disposed  in 
bundles  or  more  evenly  distributed,  but  in  either  case  the  number 
of  fibres  or  bundles  considerably  exceed  the  number  of  sub-cuticular 
muscles.  On  each  surface  a  bundle  of  transverse  fibres  follows 
them,  the  elements  of  which  penetrate  to  the  borders  of  the  segments, 
thus  passing  through  the  longitudinal  muscles  and  reaching  the  cuticle. 
The  mass  of  parenchyma  included  by  the  transverse  muscles  is 
termed  the  MEDULLARY  layer,  while  the  mass  lying  outside  them  is 
termed  the  CORTICAL  LAYER. 


ANATOMY    OF   THE    CESTODES  193 

It  was  known  long  ago  that  the  myoblasts  adhere  to  the 
dorso-ventral  fibres  as  protuberant  formations  ;  but  it  is  only  recently 
that  they  have  been  found  to  be  also  muscle  fibres  in  the  form  of  large 
star-shaped  cells,  which  are  not  close  to  the  fibres  (fig.  118),  but  are 
connected  with  them  by  offshoots  (Blochmann,  Zernecke). 

Within  the  scolex  the  direction  and  course  of  the  muscular 
layers  change. 

The  SUCKERS  are  farts  of  the  musculature,  locally  trans- 
formed, with  a  powerful  development  of  the  dorso-ventral  muscles 
into  radial  fibres.  The  ROSTELLUM  of  the  armed  tseniae,  .like  the 
rostrum  of  the  Rhynchobothridiae,  also  belongs  to  the  same  category 
of  organs. 

In  the  simplest  form,  the  rostellum  (as  in  Dipylidium  caninum 


A  m. 


FIG.  120. — Rostellum  of  Dipy-  FIG.    121.  —  Head   of    Dipylidium 

lidium    caninum.       Lm.,    longi-  caninum  of  the  dog,  with  projected 

tudinal    muscles;   Am.,    annular  rostellum.    71/1.     Am.,  annular  mus- 

muscles.  cles  ;   Sp.,  suckers. 


=Tcenia  cucumerina)  appears  as  a  closed  oval  sac,  the  anterior 
part  of  which,  projecting  beyond  the  upper  surface  of  the  head, 
carries  several  rows  of  hooks  (figs.  120  and  121).  The  entire 
internal  space  of  the  sac  is  occupied  by  an  elastic,  slightly  fibrous 
mass,  while  the  anterior  half  of  the  surface  of  the  rostellum  is 
covered  by  longitudinal  fibres  and  the  posterior  half  by  annular 
fibres.  On  contraction  of  the  latter  the  entire  mass  is  driven  for- 
wards, the  surface  of  the  rostellum  becomes  more  arched,  and  the 
position  of  the  hooks  is,  in  consequence,  altered.  The  rostellum  of 
the  large-hooked  taeniae,  wjiich  inhabit  the  intestine  of  man  and 
beasts  of  prey,  is  of  a  far  more  complicated  structure,  for,  in 
addition  to  the  somewhat  LENTIFQRM  rostellum  carrying  the  hooks 
on  its  outer  surface,  there  are  secondary  muscles  grouped  in  a  cup- 
13 


194 


THE    ANIMAL    PARASITES    OF    MAN 


like  manner  (fig.  122).  Every  change  in  the  bending  of  the 
surface  of  the  rostellum  induces  an  alteration  in  the  position  of 
the  hooks.  In  the  hookless  taeniadae  the  muscular  system  of  the 
rostellum  is  altered  in  a  very  different  manner  ;  in  a  few  forms 
a  typical -sucker  appears  in  its  place. 

The  NERVOUS  SYSTEM  commences  in  the   scolex  and  runs  through 

the  neck  and  the  entire  series  of 
proglot  tides.  Within  the  prog- 
lottides  it  consists  of  a  number 
of  medullary  fasciculi  running 
longitudinally,  and  of  which 
those  at  each  lateral  border  are 
usually  the  most  powerful.  In 
the  tcenke  the  lateral  fasciculi 
are  accompanied  both  dorsally 
and  ventrally  by  a  thinner  fasci- 
culus (concomitant  fasciculus 
(fig.  1 1 9);  on  each  surface,  more- 
over, between  the  lateral  fasci- 
culi and  the  median  plain,  there 
are  two  somewhat  stronger  fas- 
ciculi (sub-median  fasciculi),  so 
that  there  is  a  total  of  ten 
longitudinal  fasciculi.  They 
lie  exteriorly  to  the  trans- 

FIG.  122. — Longitudinal  section  of  the  head      verse     muscle     plates,    and    the 


and  neck  of  Tcenia  crassicollis.  30/1.  Lm., 
longitudinal  muscles  of  the  neck;  Lf.,  lat- 
eral fasciculi  ;  G.,  ganglion  ;  Sc.,  subcutic- 
ular  layer;  Wr,  external;  TJ^.,  interior  ex- 
cretory vessel. 


lateral  and  concomitant  fas- 
ciculi lie  exteriorly  to  the 
principal  excretory  vessels,  and 
are  everywhere  connected  by 

numerous  anastomoses  which  again  anastomose  ;  one  typical  annular 
commissure  is  usually  found  at  the  posterior  border  of  the  seg- 
ments. In  the  Bothriocephalidae  the  distribution  of  the  fasciculi  is 
different  (for  instance,  two  lie  in  the  medullary  layer),  or  they  are 
split  up  into  a  larger  number  of  branches.  In  the  scolex  the 
fasciculi  are  connected  in  a  very  remarkable  manner  by  commis- 
sures with  that  which  is  generally  termed  the  central  part  of  the 
entire  nervous  system.  There  occurs  normally  a  commissure 
between  the  two  lateral  fasciculi,  at  the  same  level,  and  the 
dorsal  and  ventral  median  fasciculi  are  also  connected  AT  EACH 
SURFACE  as  well  with  each  other  as  with  the  lateral  fasciculi,  so 
that  a  hexagonal  or  octagonal  figure  is  formed.  The  so-called  apical 


CESTODES :    EXCRETORY   ORGANS 


195 


nerves  pass  from  this  commissural  system  anteriorly,  embrace  the 
secondary  muscular  system  of  the  rostellum  semi-circularly,  and 
form  an  annular  commissure  (rostellar  ring)  at  the  inner  part  of 
the  rostellum. 

The  peripheral  nerves  arise  from  the  fasciculi,  as  well  as  from 
the  commissures  situated  in  the  scolex ;  some  go  direct  to  the 
muscles,  while  others  form  a  close  plexus  of  nerves  from  the  inner 
to  the  outer  longitudinal  muscles,  which  plexus  likewise  sends  out 
fibres  to  the  muscles,  but  principally  to  numerous  fusiform  organs 
of  sense  (fig.  118,  PI.)  ;  they  pass  between  the  subcuticular 
cells  and  reach  the  cuticle  with  their  peripheral  processes,  there 


FIG.  123. — Young  Acanthobothnum 
coronatum,  v.  Ben...  with  the  excretory 
vessels  outlined  ;  slightly  enlarged. 
(After  Pintner.) 


FIG.  124. — Scolex  of  a  cysticer- 
coid  from  Arion,  with  the  excre- 
tory vessels  outlined.  (After 
Pintner.) 


finishing  with  a  small  terminal  plate.      Higher  organs  of  sense  are 
not  known. 

The  EXCRETORY  APPARATUS  of  the  cestodes  is  similar  to  that  of 
other  flat  worms.  The  terminal  cells,  which  hardly  differ  in  appear- 
ance from  those  of  the  trematodes,  are  distributed  throughout  the 
parenchyma,  but  are  more  common  in  the  cortical  than  in  the 
medullary  layer  (fig.  118,  Ts.).  Before  reaching  a  collecting  tube, 
the  capillaries  run  straight,  tortuously,  or  in  convolutions,  they  greatly 
anastomose  with  one  another  or  form  rete  mirabile.  The  collecting 
tubes,  which  have  their  own  epithelial  and  cuticular  wall,  and  which 
also  appear  to  be  provided  with  muscular  fibres,  occur  typically  as 
four  canals  passing  through  the  entire  length  of  the  worm  (fig.  123), 
they  lie  side  by  side,  two  on  either  lateral  border  ;  in  the  head  the  two 
vessels  on  each  side  unite  by  means  of  a  loop,  at  the  posterior  ex- 
tremity they  open  into  a  short  pyriform  or  fusiform  terminal  bladder 


ig6  THE    ANIMAL    PARASITES    OF    MAN 

which  discharges  in  the  middle  of  the  posterior  edge  of  the  original 
terminal  proglottis. 

This  primitive  type  (fig.  123)  of  collective  tubes  is  subject  to 
variation  in  most  cestodes,  in  the  scolex  as  well  as  in  the  seg- 
ments. Indeed,  even  the  lumen  of  the  four  longitudinal  tubes 
does  not  remain  the  same,  because  the  dorsal  or  exterior  tubes 
are  more  fully  developed  and  become  broader,  whereas  the 
ventral  or  inner  ones  remain  small,  and  in  some  species  quite 
disappear  in  the  older  segments  (figs.  119  and  122).  Moreover, 
very  frequently  connections  are  established  between  the  right  and 
left  longitudinal  branches,  as  in  the  head,  where  a  "  frontal 
anastomosis  "  develops,  which  in  the  taeniadae  usually  takes  the  form 
of  a  wreath  encircling  the  rostellurn  (fig.  124),  and  in  the  seg* 
ments  transverse  anastomoses  form  at  each  posterior  border, 
especially  between  the  larger  branches,  and  more  rarely  between 
the  smaller  collecting  tubes  also  (fig.  125). 

The  so-called  "  island  "  formation  is  another  modification,  and 
this  may  appear  in  the  collecting  tubes  themselves  as  well  as 
in  their  anastomoses  ;  at  any  spot  a  vessel  may  divide  and  after 
a  longer  or  shorter  course  the  two  branches  reunite.  The  above- 
mentioned  ring  in  the  frontal  commissure  of  the  tajniadse  is  such 
an  island  ;  similar  rings  also  frequently  encircle  the  suckers 
(fig.  124).  In  extreme  cases  (Tricenophorus,  Ligula,  Dibolhrio- 
cephalus,  &c.)  this  island  formation  extends  to  all  the  collecting 
tubes  and  their  anastomoses.  Instead  of  two  or  four  longitudinal 
canals  only  connected  by  transverse  anastomoses  at  the  posterior 
border  of  the  segments,  there  is  an  irregular  network  of  vessels, 
situated  in  the  cortical  layer,  from  which  the  longitudinal  branches, 
having  again  subdivided,  can  only  be  distinguished  at  intervals, 
and  even  then  not  in  their  usual  number. 

The  opening  of  the  longitudinal  branches  at  the  posterior  end 
requires  more  accurate  investigation  ;  it  is  true  that  a  single 
terminal  bladder  is  mentioned  as  being  present  in  many  species, 
but  this  is  also  disputed  ;  when  the  original  end  proglottis  has 
been  cast  off,  the  longitudinal  branches  discharge  separately. 
Some  species  possess  the  so-called  foramina  secundarja,  which  serve 
as  outlets  for  the  collecting  tubes  ;  they  are  generally  at  the  neck, 
but  may  be  situated  on  the  segments. 

The  contents  of  the  excretory  vessels  is  a  clear  fluid,  the  regurgi- 
tation  of  which  is  prevented-  by  the  valves  present  at  the  points 
oi  departure  of  the  transverse  anastomoses.  The  fluid  contains  a 
substance  similar  to  a  solution  of  guanine  and[xanthine. 


CESTODES  I    GENERATIVE    ORGANS 


197 


Generative  Organs. — With  the  exception  of  one  genus  (Diceco- 
cestus,  Fuhrm.),  which  is  stated  to  be  sexually  differentiated,  all 
the  cestodes  are  hermaphroditic  ;  the  genitals  first  develop  gradually 
in  the  segments  (never  in  the  scolex),  the  male  organs,  as  is  usual 
in  hermaphroditic  animals,  forming  earlier  than  the  female.  The 
youngest  proglottides  generally  do  not  exhibit  even  traces  of 
genitals;  these,  as  a  rule,  develop  first  in  the  older  segments,  and 
the  development  proceeds  onwards  from  segment  to  segment.  In  a 
few  exceptional  cases  (Ligtda]  the  sexual  organs  are  already 


N. 


Ut, 


Vag, 


Vsc.     Shg. 


FIG.  1,25. —  Proglottis  of  Tcenia  saginata,  G.,  with  genital  organs.  10/1. 
C-,  transverse  canals  of  the  excretory  system ;  Ss.,  genital  pore ;  Vsc.,  vitellogene 
gland;  T.,  testicles;  N.,  lateral  longitudinal  nerve;  Ov.,  ovary;  Shg.,  shell  gland  ; 
Ut.,  uterus ;  Vag.,  vagina ;  V.d.,  vas  deferens ;  W.,  excretory  vessel. 

developed  in  the  cysticercus  stage,  but  are  only  functional  after  the 
introduction  of  the  parasite  into  the  terminal  host. 

With  the  exception  of  the  end  portions  of  the  vagina,  cirrus 
and  uterus,  all  the  parts  of  the  genital  apparatus  lie  in  the  medul- 
lary layer  ;  only  the  vitellaria  in  many  species  are  in  the  cortical 
layer.  The  male  apparatus  consists  of  the  testes,  of  which,  as  a 
rule,  there  are  a  large  number,1  and  which  are  in  a  dorsal  position 
from  the  transverse  plane  (fig.  119,  T.),  a  vas  efferens  springs 


1  There    are,    however,    tape-worms    with    only    one,    others    with    only    two    or 
three  testes  in   each  segment. 


THE    ANIMAL    PARASITES    OF    MAN 


from  each  testis,  unites  with  those  that  are  contiguous,  and 
finally  discharges  into  the  muscular  vas  deferens  that  is  situated 
in  about  the  middle  of  the  segment.  According  to  its  position  the 
genital  pore  opens  on  a  lateral  border  or  in  the  middle  line 
towards  the  front  ;  it  is  much  convoluted  or  twisted  and  fre- 
quently possesses  a  protuberance  termed  the  vesicula  seminalis.  It 
finally  enters  the  cirrus  pouch,  which  is  usually  extended  ;  within 
the  cirrus  pouch  lies  the  projectile  end,  the  penis,  which  is  sometimes 
provided  with  booklets . 

The  male  sexual  orifice  almost  always  lies  by  the  opening  6f 
the  vagina  in  a  genital  atrium,  the  raised  border  of  which  rises 
above  the  edge  of  the  segment  and  forms  the  genital. pore  (fig.  125). 


A. 


FIG.  126. — Central  field  of  the  proglottis  of  Dibothriocephalus  latus.  A., 
from  the  ventral  surface  ;  B.,  from  the  side.  Cp.,  cirrus  pouch  ;  Vs.,  vitellogene 
gland ;  Ov.,  ovarium  ;  Sg.,  shell  gland  ;  T.,  testicles  ;  Ut.,  uterus  ;  Va.,  vagina ; 
Vd.,  vas  deferens.  (From  Claus.) 


The  vagina,  like  the  vas  deferens,  usually  proceeds  inwardly 
or  posteriorly,  where  it  assumes  a  spindle-shaped  form  (recep- 
taculum  seminis)  ;  its  continuation,  the  spermatic  duct,  unites 
with  the  oviduct,  the  common  excretory  duct  of  the  ovaries. 
The  ovaries,  usually  two  in  number,  are  represented  by  com- 
bined tubular  glands  in  the  posterior  half  of  the  proglottis,  and 
they  spread  out  into  the  medullary  layer,  but  are  also  distributed 
spread  out  ventrally  on  the  transverse  plane. 

At  the  origin  of  the  oviduct  there  is  frequently  a  part  which 
is  dilated  and  provided  with  annular  muscles,  and  which 


CESTODES  :    GENERATIVE    ORGANS 


199 


receives  the  germinal  cells  and  advances  them  further.  After  the 
union  of  the  oviduct  with  the  spermatic  duct  the  canal  proceeds  as 
a  duct  for  fertilisation,  and  after  only  a  very  short  course  takes 
up  the  vitellogene  gland  or  glands  and  then  the  numerous  ducts 
of  the  shell  gland  (ootype).  The  vitellogene  gland  may  be  a  single 
one.  but  often  exhibits  the  primitive  duplication  more  or  less  dis- 
tinctly, in  which  case  it  is  situated  at  the  posterior  border  of  the 
segments  in  the  medullary  layer  (fig.  125).  The  original  position  of 
the  doable,  organ  is  then  the  same  as  in  the  trematodes,  i.e.,  at  the 
sides  of  the  proglottides,  and  thence  eventually  spreading  more 
or  less  on  both  aspects  (figs.  126  and  128)  ;  the  gland  is  dis- 
tinctly grape-like  and  the  follicles  lie  mostly  in  the  cortical  layer. 


Fxv.       M. 


w®$$>&  ^ 


cp. 

FIG.  127. — External  aspect  of  a  transverse  section  through  a  proglottis  of 
Teenia  crassicollis.  44/1.  Cp.,  cirrus  pouch,  with  cirrus  and  the  retractors  at 
its  base  ;  Exv.,  excretory  vessel  ;  T.,  testicles  ;  Lm.,  longitudinal  muscles  ; 
M.,  medullary  fasciculus  ;  V.d.,  vas  deferens. 


Tire  fertilised  ova,  surrounded  by  masses  of  vitellus,  receive 
the  shell  material  at  the  place  of  junction  of  the  shell  gland, 
and,  as  completed  eggs,  then  move  onward  to  the  uterus.  In  those 
cases  in  which  the  uterus  in  its  further  course  presents  a  sinuous 
canal  and  forms  a  rosette,  as  in  the  liver  fluke  (Ligula,  Triceno- 
phorus,  Schistocephalus,  Dibothriocephalus,  and  others),  there  is 
generally  an  external  opening  which  is  usually  separate  from 
the  genital  pore,  and  lies  on  the  same  or  the  opposite  surface. 
In  all  other  cases,  however,  the  uterus  terminates  blindly  and  is 
represented  by  a  longer  or  shorter  tube  lying  in  the  longitudinal 
axis  (fig.  125) ;  (in  some  forms,  however,  it  extends  transversely) 


200 


THE    ANIMAL    PARASITES    OF    MAN 


but  with  the  accumulation  of  eggs  it  becomes  modified  in  various 
ways  ;  it  sends  out  lateral  branches,  sometimes  also  forms  numerous 
little  diverticula  which  shelter  single  eggs  or  groups  of  eggs.  This 
part  of  the  female  genital  apparatus  is  not  immediately  confined 
to  the  spot  where  the  eggs  are  formed,  but  a  narrow  passage,  the 
uterine  canal,  intervenes  between  the  two. 

In  species  in  which  the  uterus  lacks  an  opening,  simultaneously 
with  the  growth  of  this  organ  an  atrophy  of  the  male  apparatus, 
at  least  of  the  testes  and  their  excretory  ducts,  takes  place  ;  this 
atrophy  also  frequently  occurs  in  the  female  germinal  glands,  so 
that  the  entire  mature  segments  have  only  separate  residues  of 
the  genitals  left,  with  the  exception  of  the  uterus. 

In  the  Acoleinae  the  vagina  is  more  or  less  further  atrophied, 
and  in  any  case  has  no  external  opening. 

A   number   of   genera   are    distinguished   by   the   duplication    of 


Vvs. 


FIG.  128. — Part  of  a  transverse  section  through  a  proglottis  of  Dibothrio- 
cephalus  latus.  .  20/1.  Ct.t  cuticle;  C.,  cirrus;  Vvs.,  vesicles  of  vitellogene  gland  ; 
Lm.,  longitudinal  muscles ;  T.,  testicles  ;  M.,  medullary  fasciculus  ;  Sc.,  sub- 
cuticle  ;  Tm.,  transverse  muscles  :  Ut.t  uterus. 

the  genitalia  in  every  segment  ;  the  genital  apparatus  in  its  entirety, 
or  with  the  exception  of  the  uterus,  is  double,  or  the  genital  glands 
and  the  uterus  are  single,  but  the  cirrus,  vas  deferens  and  vagina 
are  duplicated. 

On  comparing  the  genitalia  of  the  trematodes  and  cestodes  the 
parts  •  will  be  found  to  agree,  but  the  vagina  of  the  cestodes 
corresponds  to  the  uterus  of  the  trematodes,  and  the  uterus  of  the 
tapeworms  to  Laurer's  canal  of  the  trematodes  ;  which  in  most 
of  the  cestodes  has  lost  its  external  orifice. 


DEVELOPMENT  OF  THE  TAPEWORMS. 

Copulation. — As  each  proglottis  possesses  its  own  genital  apparatus 
and  male  as  well  as  female  organs  are  united,   the .  following  pro- 


CESTODES  I    GENERATIVE   ORGANS  2OI 

cesses  may  occur  :  (i)  Self-impregnation,  auto-fecundation  (without 
"  immissio  cirri  ").  (2)  Self-copulation,  auto-copulation  (with  immissio 
cirri).  (3)  Alternative  or  mutual  copulation  between  proglottides 
of  the  same  or  different  chains  (of  the  same  species),  and  (4) 
mutual  or  interchangeable  copulation  in  the  same  proglottis  in  the 
species  with  double  genital  pores.  These  various  modes  have 
actually  been  observed. 

In  -those  species  which  lack  the  vagina  (Acole'ince)  it  appears  that 
the  cirri,  which  are  always  furnished  with  hooks,  are  driven  into 
the  tissues  and  thus  come  into  contact  with  the  receptaculum  seminis. 

The  eggs  of  all  cestodes  are  provided  with  shells,  but  the 
shells,  like  their  contents,  vary.  In  genera  that  possess  an  uterine 
orifice  the  mature  eggs  frequently  do  not  differ  from  those  of  the 


FIG.     129. — Egg    of   Diplo-  FIG.  130. — Uterine  egg  of  Tcenia  saginata,  G. 

gonoporus      grandis.        440/1.  Shell  with    filaments;     the    oncosphere    with 

(After  Kurimoto.)  embryonal  shell  in  the  centre.    500/1.    (After 

Leuckart.) 


Fasciolidse  ;  they  have  a  brown  or  yellow  shell  of  oval  form  pro- 
vided with  an  operculum,  and  contain  a  number  of  yolk  cells  in 
addition  to  the  fecundated  germinal  cell  (fig.  129).  In  other  cases 
the  lid  is  absent  and  the  egg-shell  is  very  thin.  In  regard  to  their 
eggs,  these  forms  approach  those  cestodes  in  which  the  secretion 
of  the  vitellogene  gland  is  a  light  albumin-like  substance  that  con- 
tains only  a  few  granules,  and  the  egg-shell  is  very  delicate  and 
without  operculum. 

The  'embryonal  development  in  most  species  takes  place  during  the 
stay  of  the  eggs  in  the  uterus ;  in  other  species  it  takes  place  after 
the  eggs  have  been  deposited  and  are  in  the  water.  Always 
separate  cells  or  a  layer  of  cells  separate  from  the  segmentation 
cells,  as  well  as  from  the  embryonal  cells,  and  form  one  or  more 
envelopes  round  the  embryo  ;  usually  two  such  envelopes  are  formed, 
the  inner  one  of  which  stands  in  intimate  relationship  with 
the  embryo  itself  and  is  often  erroneously  termed  the  egg-shell. 


2O2  THE    ANIMAL   PARASITES   OF   MAN 

In  some  species  it  carries  long  cilia,  by  aid  of  which  the  young 
swim  about  when  released  from  the  egg-shell  ;  as  a  genera 
rule,  however,  there  are  no  cilia  and  the  integument  is  homo- 
geneous, or  is  composed  of  numerous  rods  and  is  calcified  (fig.  130). 
The  exterior  envelope  (investing  integument)  lies  close  to  the  egg- 
shell and  remains  within  it  when  the  ciliated  embryo  hatches 
out,  and  in  many  species  it  perishes  at  the  end  of  the  embryonal 
development  with  the  delicate  egg-shells,  so  that  one  observes  not 
the  entire  ovum,  but  only  the  embryo  in  its  embryonal  shell 
(fig.  131,  a). 

The  embryo  enclosed  within  the  embryonal  shell,  the  ONCOSPHERE, 
is  of  spheroid  or  ovoid  form  (fig.  131,  b),  and  is  distinguished  by 
the  possession  of  three  pairs  of  booklets,  a  few  terminal  cells,  and 
is  provided  with  muscles  to  move  the  hooklets. 

No  FURTHER  DEVELOPMENT  of  the  oncosphere  takes  place  either 


FIG.  131. — a.,  Oncosphere,  with  shell 
of  Tcsnia  africana  greatly  magnified)  after 
von  Linstow)  ;  b.,  freed  oncosphere  of 
Dipylidium  caninum  (greatly  magnified) 
(after  Grassi  and  Rovelli). 


in  the  parent  organism  or  in  the  open  ;  in  fact,  in  all  cases  in 
which  the  oncospheres  are  already  formed  within  the  proglottides 
they  do  not  become  free,  but  remain  in  their  enveloping  sheath  ; 
it  is  only  when  the  oncospheres  are  provided  with  a  ciliated 
integument,  that  they  leave  the  egg-shell,  and  even  cast  off  the 
ciliated  integument,  after  having  swum  about  in  water  for  some 
time.  Sooner  or  later,  however,  all  the  oncospheres  leave  the 
host  that  harbours  the  parental  tapeworm  and  reach  the  open, 
either  still  enclosed  in  the  uterus  of  the  evacuated  proglottides,  after 
the  disintegration  of  which  they  become  free,  or  (as  eggs  with 
shells)  after  being  deposited  in  the  intestine  of  the  host,  which 
they  leave  with  the  faeces  ;  in  the  former  case,  the  slightest  injury 
to  the  mature  proglottides  while  still  in  the  intestine  suffices  to 
allow  a  part  of  the  oncospheres  with  their  integument  to  be 
released  and  mingled  with  the  faeces  ;  they  have  then  been  erro- 
neously termed  "  eggs  of  Taeniae." 

In  any  case,  however,  the  oncospheres  must  be  transmitted  into 


CESTODES  :    GENERATIVE    ORGANS  203 

suitable  animals  to  enable  their  further  development  ;  in  only 
very  rare  cases  an  active  invasion  might  be  possible,  as,  for  instance, 
takes  place  with  the  miracidia  of  many  trematodes.  The  entry 
into  an  animal  is,  as  a  rule,  entirely  passive,  that  is  to  say,  the 
oncospheres  are  swallowed  with  the  food  or  water.  Many  animals 
are  coprophagous  and  ingest  the  oncospheres  direct  with  the  faeces, 
others  swallow  them  with  water,  mud,  or  food  contaminated  by  such 
faeces.  Infection  is  easily  produced  artificially  by  feeding  suitable 
animals  with  mature  proglottides  of  certain  cestodes  or  intro- 
ducing the  oncospheres  with  the  food.  As  the  mature  tapeworm 
frequently  finds  the  conditions  suitable  for  its  development  in  only 
one  species  of  host,  or  in  species  nearly  related,  and  perishes  when 
artificially  introduced  into  other  hosts,  experience  has  taught  us 
that  to  succeed  in  cultivating  the  oncospheres  certain  species  of 
animals  are  necessary.  Thus  we  are  aware  that  the  oncospheres  of 
Tcenia  solium,  which  lives  in  the  intestine  of  man,  develop  only 
in  the  pig,  and  only  quite  exceptionally  develop  into  the  stage 
characteristic  of  all  cestodes — the  cysticercus — in  a  few  other  mam- 
mals. The  oncospheres  of  Tcenia  -  saginata  develop  further  only 
in  the  ox,  those  of  Tcenia  marginata  (of  the  dog)  in  the  pig  and 
sheep  ;  those  of  Tcenia  serrata  (of  the  dog)  in  hares  and  rabbits  ; 
those  of  Dipylidium  caninum  (of  the  dog  and  cat)  in  parasitic 
insects  of  the  dog  and  cat,  &c.,  &c.  It  is  not  unusual  that  young 
animals  only  appear  to  be  capable  of  infection,  while  older  animals 
of  the  same  species  are  not  so. 

Once  introduced  into  a  suitable  animal,  which  is  only  excep- 
tionally the  same  individual  or  belongs  to  the  same  species  to 
the  one  which  harbours  the  adult  tapeworm,  the  oncosphere  passes 
into  the  cysticercus  stage  common  to  all  cestodes,  but  varying  in 
structure  according  to  the  species  ;  in  the  simplest  case  such  a 
cysticercus  resembles  the  scolex  of  the  corresponding  tapeworm,  as 
in  Dibothriocephalus,  only  that  the  head,  provided  with  suckers,  is 
retracted  within  the  forepart  of  the  neck.  The  conditions  appear 
to  be  similar  in  Ligula,  Schistocephalml  Tricenophorus,  but  here  the 
cysticercus  is  very  large,  indeed,  as  large  in  the  first-mentioned 
genera  as  the  tapeworm  originating  from  it,  and  the  sexual 
organs  are  already  outlined ;  doubtless,  however,  this  stage  is 
preceded  by  one  that  corresponds  to  the  scolex  of  the  genus  in 
question,  and  which  represents  the  actual  cysticercus  stage.  In 
such  cases  the  development  of  the  body  of  the  tapeworm  from  the 
scolex  already  sets  in  within  the  preceding  or  intermediary  host ; 
in  other  cases,  except  in  the  single-jointed  cestodes,  this  only 


204 


THE    ANIMAL    PARASITES    OF    MAN 


takes  place  in  the  definitive  host.  In  the  cysticercus  stages  of  other 
tapeworms  we  can  always  distinguish  the  scolex  and  a  caudal- 
like  vesicular  or  compact  appendix.  The  scolex  alone  forms 
the  future  tap'eworm,  the  variously-formed  appendix  perishing. 

It  has  now  been  proved  that  the  appendix,  the  caudal  vesicle, 
originates  direct  from  the  body  of  the  oncosphere,  and  therefore  is 
primary,  and  that  the  scolex  only  subsequently  forms  through  pro- 
liferation within  this  appendix.  On  account  of  this  origin  the  scolex 
is  generally  regarded  as  the  daughter,  and  the  part  usually  designated 
as  the  appendix  as  the  mother,  originating  from  the  oncosphefe. 

Accordingly,  two  modes  of  development  of  the  cysticercus  stage 
may  be  distinguished  ;  in  the  one  case  the  oncosphere  changes 
direct  into  the  scolex,  thus  forming  the  body  of  the  tapeworm  within 
the  primary  host  ;  in  the  other  case  the  scolex  only  forms 
secondarily  in  the  transformed  body  of  the  oncosphere,  which 


FIG.  132. — -Plerocercus  of  Tetrar- 
hynchus.      20/1. 


FIG.  133. — Young  cysticerci  of  Tcenia 
saginata,  G.  (magnified).  On  the  left 
seen  from  above,  on  the  right  optical 
section  with  rudiment  of  scolex.  (From 
Leuckart.) 


later  on  perishes,  the  scolex  alone  remaining  as  the  originator  of 
the  tapeworm  colony. 

The  direct  metamorphosis  of  the  oncosphere  into  the  cysticercus 
form  termed  plerocercoid,  has  hitherto  not  been  investigated, 
although  Ligula,  Schistocephalus  and  Bothriocephalus  are  very  com- 
mon parasites,  but  many  circumstances  point  to  the  conclusions 
arrived  at  by  us  and  by  other  observers. 

In  a  broad  sense,  our  knowledge  of  the  development  of  the 
cysticerci  is  limited  almost  exclusively  to  that  of  a  few  "  cystic 
worms  "  ;  in  other  cases  we  know  either  only  the  terminal  stage, 
the  complete  cysticercus,  or,  exceptionally,  one  of  the  intermediary 
stages,  but  we  are  not  acquainted  with  a  complete  series ;  the 
description  must  therefore  be  incomplete. 

We    know    from    feeding    experiments   that,    after    the    intro- 


CESTODES  :    GENERATIVE   ORGANS  205 

duction  of  mature  proglot tides  or  of  the  .fully  developed  ova  of 
Tcenia  crassicollis  (of  the  cat)  into  the  stomach  of  mice,  the 
oncospheres  escape  from  the  shell  in  the  middle  portion  of  the 
small  intestine,  and  a  few  hours  later  penetrate  into  the  intestinal 
wall  by  means  of  a  boring  movement ;  they  have  been  found  in 
this  position  twenty-seven  to  thirty  hours  after  the  infection.  By 
means  of  this  migration,  for  which  purpose  they  employ  their 
hooks,  they  attain  the  blood-vessels  of  the  intestine,  indeed,  already 
nine  hours  after  the  infection  and  later  they  are  found  in  the  blood 
of  the  portal  vein,  and  in  the  course  of  the  second  day  after  infection 
they  are  found  in  the  capillaries  of  the  liver,  which  this  species  does 
not  leave. 

Leuckart,  in  experimental  feeding  of  rabbits  with  oncospheres 
of  Tcemia  serrata  (of  the  dog),  found  free  oncospheres  in  the  stomach 
of  the  experimental  animal,  but  not  in  the  intestine ;  however, 
he  came  across  them  again  in  the  blood  of  the  portal  vein.  The 
way  through  blood-vessels  to  the  liver  is  the  normal  path  for 
those  species  of  Taenia,  the  offspring  of  which  become  cysticerci  in 
mammals  ;  and  this,  even  in  those  cases  in  which  the  oncospheres 
develop  further  in  the  omentum  or  in  the  abdominal  cavity  (Cysti- 
cercus  tenuicollis,  C.  pisiformis),  for  here  also  distinct  alterations  are 
observable  in  the  liver,  that  lead  one  to  the  conclusion  that  there 
has  been  a  secondary  migration  out  of  the  liver  into  the  abdominal 
cavity.  Indeed,  one  must  not  imagine  that  the  young  stages  of 
the  cestodes  are  absolutely  passive  ;  once  they  have  invaded  an  organ 
they  travel  actively,  and  leave  distinct  traces  of  their  passage. 

In  other  cases  the  oncospheres  leave  the  liver  with  the  circula- 
tion, and,  are  thus  distributed  further  in  the  body  ;  they  may 
settle  and  develop  in  various  organs,  or  they  may  only  do  so 
in  certain  organs.  Many  oncospheres  may,  by  travelling  through 
the  intestinal  wall,  penetrate  through  it  and  attain  the  abdominal 
cavity  direct ;  some  also  reach  it  by  means  of  the  lymph  stream. 
Where  there  are  no  blood  and  lymphatic  vessels  in  the  intestinal 
wall,  as  in  insects,  the  oncospheres  attain  the  body  cavity  or  its 
organs  direct ;  in  short,  they  never  remain  in  the  intestinal  lumen 
itself,  and  only  rarely — as  in  Hymenolepis  murina  of  the  rat — do 
they  remain  in  the  intestinal  wall. 

When  the  .infection  has  been  great,  and  the  body  is  crowded  with 
numerous  oncospheres,  acute  feverish  symptoms  are  induced  to  which  the 
infected  animals  usually  succumb  ("  acute  cestode  tuberculosis  ")  ;  while  in 
other  cases  the  alterations  in  the  organs  attacked — as  the  liver  in  mice,  and 
the  brain  in  sheep — may  cause  death. 


206 


THE    ANIMAL    PARASITES    OF    MAN 


Sooner  or  later  the  oncospheres  of  tapeworms  come  to  rest, 
and  are  first  transformed  into  small  cysts,  which  may  be  round  or 
oval  according  to  the  species.  The  embryonal  hooks  disappear  sooner 
or  later,  or  remain  close  together  or  spread  over  some  part  of  the 
cyst  (fig.  134,  b).  Their  discovery  by  v.  Stein  in  the  bladder-worm 
of  the  larva  of  Tenebrio  molitor  first  led  to  the  conclusion  that  the 
cysticerci  actually  originate  from  the  oncospheres  of  Tseniae. 

The  cyst  may  remain  as  a  cyst,  and  then  by  proliferation  the 
scolex  forms  within  it  (fig.  136),  or  it  may  divide  into  an  anterior 
cystic  portion  and  a  solid  tail-like  appendix  of  various  length,  on 
which  the  embryonal  hooks  are.  to  be  found,  and  this  is  particularly 


FIG.  134. — Cysticercoid  of  Avion  ater.  50/1.  (a]  In  the  contracted  condition. 
(b)  In  the  extended  state  with  the  embryonal  hooks  maintained,  and  with 
water  vessels,  &c. 


the  case  in    regard    to  those  species  of    Taenia   (cysticercoids)   that 
develop  in  invertebrate  animals,  such  as  arthropoda. 

As  mentioned  above,  the  scolex  is  understood  to  be  an 
individual  that  originates  through  proliferation  of  the  wall  of  the 
parent  cyst,  mostly  singly,  but  in  those  cystercerci  that  are  termed 
Cce-nurus  (fig.  135)  many  occur,  whereas  in  the  cysticercus  stage  of 
Echinococcus  the  parent  cyst  originating  from  the  oncosphere  of 
Tcenia  echinococcus  (of  the  dog)  first  produces  a  number  of  daughter 
cysts,  which  in  their  turn  form  numerous  scolices.  Echinococcus- 
like  conditions  also  occur  in  cysticercoids,  as,  for  instance,  in 
those  peculiar  to  earthworms ;  and  similar  conditions  prevail  in  a 


CESTODES  I     GENERATIVE    ORGANS 


207 


form  of  cysticercus  known  as  Staphylocystis,  and  found  in  the 
woodlouse  (Glomcris).  Thus  it  happens  that  finally  one  tape- 
worm egg  produces  not  one,  but  numerous  tapeworms,  for,  under 
favourable  conditions,  each  scolex  can  form  a  tapeworm. 


FIG.  135. — Section  through 
a  piece  of  a  Ccenuris  cerebralis, 
with  four  cephalic  cones  in 
different  stages  of  develop- 
ment. (From  a  wax  model.) 


FIG.  1 36.  —  Median  section 
through  a  Cysticercns.  with  com- 
plete scolex.  (After  Leuckart.) 


As  the  foundation  of  the  scolex  there  appears  a  hollow  bud,  the  cephalic 
cone,  usually  directed  towards  the  interior  of  the  bladder  cavity  ;  on  its  internal 
surface   arise    the    four    suckers,    and    the    rostel-lum    with    the    hook    appa- 
ratus is  formed  in  its  blind  end  ;   it  will    thus  be  ob- 
served  that   the  head  of  a  Taenia  is   formed  with  the 
parts  inside  out  (fig.  136}.     In  many  cysticerci  the  head 
forms  at    the  base  of   the   cephalic  cone,  and  is  sub- 
sequently invaginated.     A  more  or  less  elongated  piece 
of  neck  also  develops,  and  even  proglottides  may  appear, 
as  in  Cysticercus  fasciolaris  of  the  Muridae  (appertaining 
to   Tcenia  crassicoilis  of   the  cat),   a  process  somewhat 
analogous  to  that  of  Ligula,  &c. 


The  period  that  elapses  from  the  time  of 
infection  till  the  Cysticercus  is  fully  developed 
varies  according  to  the  species ;  the  cysticercus 
of  Tcenia  saginata  requires  twenty-eight  weeks, 
that  of  Tcenia  marginata  seven  to  eight  weeks, 
that  of  Tcenia  solium  three  to  four  months, 
and  that  of  Tcenia  echinococcus  longer  still. 

With   one   single    exception   (Archigetes)   the 
cysticerci   do   not    become  mature  in  the  place 
where   they  developed  ;    they   must   be  enabled 
to    enter    the   terminal    host,   a   matter  that   is 
usually  purely  passive,  the  carriers  of  the  cysticerci  or  infected  parts 
of  animals  being  usually  devoured  by  other  animals.     In  this  manner, 
for  instance,  the  cysticerci  of  mice  and  rats  (Cysticercus  fasciolaris} 


FIG.  137. — Cysticer- 
cus pisiformis  in  an 
evaginated  position. 
18/1. 


208  THE    ANIMAL    PARASITES    OF    MAN 

reach  the  intestine  of  cats,  those  of  the  hare  and  rabbit  (Cysti- 
cercus  pisiformis)  reach  the  intestine  of  hounds  ;  those  of  the  pig 
(Cysticercus  cellulose)  are  introduced  into  man,  those  of  insects  are 
swallowed  by  insectivorous  birds,  those  of  crustaceans  are  ingested 
by  ducks  and  other  water  fowl  ;  perhaps,  also,  the  infection  of 
herbivorous  mammals  is  caused  by  their  having  accidentally 
swallowed  smaller  creatures  invaded  by  cysticerci.  Of  course,  the 
researches  of  Grassi  and  Rovelli  have  taught  us  that  such  an 
intermediary  host  is  not  always  necessary  ;  the  Tcenia  murina  of 
rats  and  mice  in  its  cysticercus  stage  lives  in  the  intestinal  wall 
of  these  rodents,  and  as  a  cysticercus  it  breaks  into  the  intestinal 
lumen  and  develops  into  a  tapeworm  in  exactly  the  same  way 
as  the  cysticerci  of  other  species  that  reach  the  intestine  of  the 
terminal  host  by  means  of  an  intermediary  carrier.  Probably 
the  curtailed  manner  of  transmission  also  occurs  in  rnariy  other 
species.  In  some  cases  the  cysticerci  quit  the  body  of  the  inter- 
mediary host  actively  as  Ligula  and  Schistocephalus,  which  travel 
out  of  the  body  cavity  of  infected  fishes  and  reach  the  water, 
where  they  may  be  observed  in  hundreds  in  summer,  at  all  events 
in  some  localities.  The  cysticercus  stage  of  Calliobothrium — wrongly 
termed  scolex — has  been  observed  swimming  free  in  the  sea,  and 
the  scolices  of  Rhynchobothrium,  without  their  parent  cysts,  have  been 
observed  free  within  the  tissues  of  some  marine  animals.  Tn  any 
case  there  is  almost  always  a  change  of  hosts  even  in  the  single- 
jointed  cestodes,  for  the  cysticercus  of  Caryophyll&us,  which  lives  in 
fishes  of  the  carp  family,  is  found  in  Oligochreta,  that  of  Gyrocotyle 
(chimaera)  in  shell-fish  (Mactra)  and  different  conditions  can  hardly 
be  possible  for  Amphilina.  Archigetes  alone  becomes  sexually  mature 
in  the  cysticercus  stage,  but  the  life-history  of  this  creature  is  not 
well  known,  so  that  it  is  not  impossible  that  the  attainment  of  sexual 
maturity  as  a  cysticercus  in  an  invertebrate  animal  (Oligochseta) 
is  perhaps  abnormal,  and  somewhat  analogous  to  the  maturity 
of  some  encysted  trematodes. 

The  METAMORPHOSIS  OF  THE  CYSTICERCUS  into  the  tapeworm  is 
rarely  accomplished  in  a  simple  manner  ;  the  transformation,  how- 
ever, is  not  complex  in  the  single-jointed  cestodes,  nor  in  Ligula 
and  Schistocephalus  ;  the  latter  is  swallowed  by  birds  (Mergus, 
Anas,  &c.),  produces  eggs  after  only  a  few  days,  and  very  soon 
quits  the  intestine  of  its  terminal  host.  In  all  other  cases  it  is 
the  scolex  only  which,  by  proliferating  at  its  posterior  extremity, 
forms*  the  proglottides,  after  having  invaded  as  a  cysticercus 
the  intestine  of  a  suitable  host.  All  parts  belonging  to  such 


CESTODES  :    BIOLOGY 


209 


cysticerci,  as,  for  instance,  the  mother  or  daughter  cyst,  and  a 
piece,  sometimes  segmented,  that  is  present  between  the  latter  and 
the  scolex  (fig.  76),  with  the  exception  of  the  scolex  or  scolices,  die 
off,  are  digested,  absorbed,  or  perhaps  even  evacuated.  It  is  not 
certain  whether  the  cysticerci  of  the  Bothriocephalina  lose  any  part, 
probably  they  do  not. 

The  time  required  by  the  scolex  to  complete  the  entire  chain 
of  proglottides  does  not  depend  only  on  the  number  it  has  to 
produce,  for  Tcenia  echinococcus,  which,  as  a  rule,  only  possesses 
three  or  four  segments,  takes  quite  as  long  a  time  for  their 
growth  (eleven  to  twelve  weeks)  as  Tcenia  solium  with  its 
numerous  segments  ;  Tcenia  ccenurus  is  fully  developed  in  three 
to  four  weeks,  and  the  same  holds  good  for  Dibothriocephalus  latus, 
which  possesses  many  more  segments  than  the  above-mentioned 
taenia  of  the  dog.  In  a  number  of  species  it  has  been  possible 
to  follow  the  average  daily  growth  and  register  it  almost  accurately  ; 
for  instance,  in  Dibothriocephalus  latus  the  daily  growth  is  8  cm., 
in  Tcenia  saginata,  7  cm.,  &c. 

The  history  of  the  development  of  the  cestodes  demonstrates 
that  human  beings  and  animals  that  harbour  tapeworms  in  their 
intestines  acquire  them  by  ingesting  the  respective  cysticercus  stages 
living  in  other  animals  (mostly  with  food) ;  it  also  shows  that  persons 
and  beasts  harbouring  these  cysticerci  may  have  become  infected 
by  having  swallowed  the  oncospheres  of  the  species  of  tapeworm 
to  which  they  belong.  In  regard  to  Tcenia  murina  alone,  it*  is 
known  that  the  introduction  of  the  oncospheres  into  those  species 
of  animals  which  may  harbour  the  adult  tapeworm  leads  to  the 
formation  of  the  latter  after  the  development  of  a  cysticercus  stage 
in  the  intestinal  wall ;  nevertheless  only  young  animals  (rats)  are 
capable  of  infection,  for  a  previous  infection,  or  the  presence  of 
mature  tapeworms  in  the  intestine,  appears  to  produce  a  kind  of 
immunity. 

BIOLOGY. 

In  their  adult  stage,  the  tapeworms  inhabit  almost  exclusively 
the  alimentary  canal  of  vertebrate  animals,  the  small  intestine 
being  the  chief  abode  with  but  few  exceptions ;  a  few  species 
select  definite  parts  of  the  intestine.  A  small  number  of  Rhyn- 
thobothriidse  of  marine  fishes  live  apparently  always  in  the 
stomach,  while  in  rays  and  sharks  the  spiral  intestine  is  their 
special  seat.  Bothriocephali  generally  attach  themselves  with 

14 


2IO  THE   ANIMAL    PARASITES    OF   MAN 

their  head  on  to  the  appendices  of  the  pylorus  of  fishes  ;  other 
species  (Hymenolepis  diminuta)  occasionally  fix  their  heads  in 
the  ductus  choledochus,  and  this  is  more  frequent  still  in  the 
tapeworms  of  the  Hyrax,  which  occasionally  penetrate  entirely 
into  the  biliary  ducts.  [Dr.  Theiler  of  Pretoria  has  sent  me  a  new 
tapeworm  which  invades  the  liver  of  sheep  in  the  Transvaal. — F.V.T.] 

In  the  diseases  of  sheep  induced  by  cestodes,  the  worms  have 
been  observed  also  in  the  pancreas.  Specimens  found  in  the 
large  intestines  were  probably  being  evacuated. 

The  cestodes  are  looked  upon  as  fairly  inert  creatures ;  this 
opinion  having  been  formed  by  observing  their  condition  in  the 
cold  cadavers  of  warm-blooded  animals.  Actually,  however,  they  are 
exceedingly  active  and  accomplish  local  movements  within  the 
intestine,  for  they  have  been  found  in  the  ducts  communicating 
with  the  bowel,  or  in  the  stomach,  and  may  even  make  their 
way  forward  into  the  oesophagus. 

They  also  invade  other  abdominal  organs  through  abnor- 
mal communications,  or  through  any  that  may  be  temporarily  open 
between  the  intestine  and  such  organs  ;  they  thus  reach  the 
abdominal  cavity  or  the  urinary  bladder,  or  they  work  their  way 
through  the  peritoneum. 

They  produce  changes  in  the  intestinal  mucous  membrane  at 
the  place  of  their  attachment,  the  alterations  varying  in  intensity 
according  to  the  structure  of  the  clinging  organs.  The  mucous 
membrane  is  elevated  in  knob-like  areas  by  the  suckers ;  the 
epithelial  cells  become  atrophied  or  may  be  entirely  obliterated. 
Dipylidium  caninum  bores  into  the  openings  of  Lieberkuhn's 
glands  with  its  rostellum,  dilating  the  lumen  to  two  or  three 
times  its  normal  size,  while  the  suckers  remain  fixed  between  the 
basal  parts  of  the  .cells.  Species  with  powerful  armatures  pene- 
trate deeper  into  the  submucosa,  and  some  that  are  not  pro- 
vided with  exceptionally  strong  armatures  or  are  even  unarmed,  may 
be  actually  found  with  the  scolex  embedded  in  the  muscles  of  the 
intestinal  walls  or  even  protruding  beyond  (Tania  tetmgona,  Mol.,  in 
fowls,  &c.).  Other  species,  again,  even  cause  perforation  of  the 
walls  of  the  intestine  of  their  hosts. 

THE  LENGTH  OF  LIFE  OF  THE  ADULT  TAPEWORMS  certainly 
varies  ;  as  a  rule  it  appears  to  last  only  about  a  year  ;  in"  other 
cases  (Ligula)  it  averages  only  a  few  days,  but  we  are  likewise 
aware  that  certain  species  of  cestodes  of  man  attain  an  age  of 
several  or  many  years  (thirty-five).  The  natural  death  of  -ces- 


CESTODES  :    BIOLOGY  211 

todes  often  appears  to  be  brought  about  by  alterations  in  the  scolex, 
such  as  loss  of  the  hooks,  atrophy  of  the  suckers  and  ros- 
tellum,  finally  the  dropping  off  of  the  scolex ;  it  is  unknown 
whether  the  chain  of  segments  deprived  of  its  scolex  likewise 
then  perishes  or  first  attains  maturity.  It  has  already  been  men- 
tioned that  in  a  few  species  the  foremost  proglottides  are  trans- 
formed into  organs  of  attachment  on  the  normal  loss  of  the  scolex. 
Abnormalities  and  malformations  are  encountered  relatively  frequently 
in  the  Cestodes — such  as  abnormally  short  or  long  segments  ;  the  so-called 
triangular  tapeworms,  which — if  belonging  to  the  tsenia — always  possess  six 
suckers ;  often  also  club-shaped  segments  occur  between  normal  ones,  or 
there  may  be  a  defect  (fenestrated  segments)  in  one  segment  or  in  the  centre 
of  a  number  following  one  another  ;  bifurcated  chains  of  segments  have  likewise 
been  observed,  as  we'll  as  incomplete  or  complete  union  of  the  proglottides, 
abnormal  increase  of  the  genital  pores,  reversion  of  the  genitalia.  Besides 
the  above-mentioned  increase  of  the  number  of  suckers  on  the  scolex 
(in  taenia),  there  maybe  a  decrease  in  the  number;  in  other  cases  the  crown 
of  hooks  may  be  absent,  or  abnormally-shaped  hooks  may  be  formed. 

LITERATURE. 

The  literature  of  the  Cestodes  up  to  1895  is  comprised  in  my  work  on 
Cestodes,  in  Bronn's  Cl.  u.  Ordn.  d.  Thierr  (iv.,  2).  Of  the  more  recent  works 
the  following  deserve  mention  : — 

BLANCHARD,    R.      Sur   quelq.   Cest.    monst.      (Progr.    med.,    1894   [2],   xx.) 
BRANDES,   G.      Teratolog.   Cestod.      (Ztsch.   f.   Nat.,    1899,   Ixxii.,   p.    105.) 
BLOCHMANN,  F.      Die  Epithelfr.  b.  Cest.  u.  Trem.  Hbrg.,    1896. 
CATTAERT,  P.  A.      Contr.  a  1'et.  d.  Ten.  triedr.      (Arch,  parasit.,   1899,  ii.,  p.   153.) 
COHN,  L.     Z.  An.   d.  Vogelcest.      (Z.   f.  w.   Zool.,    1900,   Ixvii.,  p.   255.) 

Unters.   lib.   d.   centr.    Nervens.    der  Cest.     (Zool.    Jahrb.    An.,    1898,   part   xii., 

p.   89.) 
Z.   Anat.   u.   Syst.   d.   Vogelcest.      (Nov.  Act.   Ac.   Caes.  Leop. -Carol.  Nat.  Cur., 

Ixxix.,  No.   3,  Halle,   1901.) 
FUHRMANN,  O.      Arbeiten  iiber  Vogeltaenien  in  :  Rev.  suiss.  de  Zool.  et  Ann.  Mus. 

d'hist.    nat.    Geneve,    iii.,   iv.,    v.,    vii.  ;    C.    f.    B.,    P.    u.    I.    [i],    xxvi. 
Ueb.  Prosthecocotyle.     (Ibid.,  xxv.) 
Neuere  Vogelcest.       (Ibid.,  xxix.) 

JACOBI,  A.      Diploposthe  laevis.      (Zool.   Jahrb.,    1897,  x.) 
LUKE,    M.      Beitr.    z.    Kenntn.    d.    Bothriocephaliden.       (C.    f.    B.,    P.    u.    L,    1899 

[i],  xxvi.,  p.   720  ;    1900,   xxvii.,   p.    200.) 

Z.   Anat.   u.   Syst.   d.   Bothr.      (Verb.   d.   D.   zool.   Ges.,    1899,   p.    30.) 
Unters.   iib.   Bothr.   mit.   marg.   Genit.     (Z.   f.   w.   Zool.,    1900,   Ixviii.) 
Revis.   m.   Bothr.-Syst.      (C.   f.   B.,   P.   u.   I.   [i],   Orig.,    1902,   xxxi.,  p.    318.) 
PINTNER,  TH.      Rhynchodaaldriis.  b.  Tetrarh.       (Arb.  zool.   Inst.  Wien.,    1899,  xii.) 
RIGGENBACH,    E.     Genus   Ichthyotaenia.       (Rev.    Zool.    Suisse,    1896,   iv.) 
STILES,  CH.  W.,  and  A.   HASSAL.      Tapeworms  of  Poultry.      U.   S.   Dep.  of  Agric. 

Bur.  of  an  Ind.   Bull.,    12,  Wash.,    1896.) 
STILES,    CH.    W.      Rev.    of   ad.    Tapew.    of   Hares   and    Rabb.      (Proc.    U.    S.    Nat. 

Mus.,   1896,  xix.) 

VAULLEGERAD,  A.     Rech.  s.  1.  Tetrarhynq.,  These,   Paris,   1899. 
WOLFFHUGEL,   K.     Beitr.  z.   Kenntn.  d.  Vogelhelm.  In.-Diss.,  Basel,   1900. 
ZERNECKE,  E.     Unters.  iib.  d.  fein.  Bau  d.  Cest.    In.-Diss.,  Rostock,    1895. 
ZSCHOKKE,   F.      Cest.   d.    Mars.   u.  Monotr.      (Semon:    Zool.    Forsch.   in    Austr.    u. 

d.  Mai.  Arch.   [Jen.  Denkschr.,   1898,  viii.],  v.) 
Neue  Stud,  an  Cest.  aplac.  Saugeth.     (Z.  f.  w.  Zool.,   1899,  lxv.f  p.  404. > 


212  THE   ANIMAL   PARASITES   OF   MAN 


THE  CLASSIFICATION  OF  THE  CESTODES. 

The  classification  of  the  Cestodes,  like  that  of  the  Trematodes,  has  so  far 
been  undertaken  by  a  number  of  investigators,  but  has  not  yet  been  definitely 
concluded.  The  genera,  numbering  about  eighty,  are  classified  in  the  following 
manner  : — 

I.  Bothriocephaloidea.  Scolex  armed  or  unarmed,  with  two  usually  slightly 
developed  groove-like  suckers  on  the  flat  surface  ;  the  external  segmen- 
tation may  be  absent  or  distinct  ;  three  genital  orifices  ;  the  genitalia 
rarely  duplicated  ;  numerous  follicles  of  vitellaria,  situated  in  the 
lateral  field  and  mostly  in  the  cortical  layer.  The  eggs  are  similar  to 
those  of  the  Fasciolidea,  but  do  not  always  possess  a  lid. 

Fam.  i.  Dibothriocephalidfs .  The  suckers  are  variously  developed  : 
by  coalescence  of  the  free  borders  they  may  be  transformed  into 
suctorial  tubes,  or  may  be  replaced  by  a  cephalic  suctorial  organ. 
The  uterus  forms  a  rosette  ;  eggs  are  provided  with  lids. 

(1)  Subf.  Ligulines  (Ligula,   Schistocephalus}. 

(2)  „      DibothriocephalincB  (Dibothriocephalus ,  Diplogonoporus,  &c.). 

(3)  »      Cyathocephalince  (Diplocotyle,  Cyathocephalus,  Bothrimonus}. 

(4)  '    „       TricBnophorince  (Fistulicola,  Ancistrocephalus,  Trianophorus , 

&c.). 

Fam.  2.  PtycHobothriida.  Scolex  unarmed  ;  the  uterus  does  not  form 
a  rosette,  but  presents  a  spacious  uterine  cavity.  The  eggs  have  a 
thin  shell  and  no  lid. 

(1)  Subf.  Amphicotylince  (Amphicotyle ,  Abothrium,  &c.). 

(2)  „       Ptychobothriince  (Ptychobothrium,   &c.). 

Fam.  3.  Amphitretidce.     Vitellogene  gland  in  the  medullary  layer  ;  uterus 

with  cavity  ;  eggs  with  thin  shells  without  lids  (Amphitretus,  &c.). 

II.  Tetraphyllidea.      Scolex     armed    or    unarmed,    with    four    very     motile 

pedunculated  or  sessile  bothridia,  or  with  four  round  suckers  ;  segmentation 

always  distinct ;  no  uterine  orifice  ;    the  cirrus  and   vagina   open   at   the 

border  ;  the  follicles  of  the  vitellaria  in  the  side  fields   or  at  the  borders, 

in  the  cortical  layer.     Eggs  thin-shelled  ;  no  lid. 

Fam.  i.  Onchobothriidce.  There  are  always  hooks  in  the  sessile  or 
pedunculated  bothridia,  in  addition  to  accessory  suckers  or  areoles 
(Onchobothrius ,  Calliobothrium,  &c.). 

Fam.  2.  Phyllobothriidce .      Bothridia   mostly   pedunculated,  simple,    or 
with  accessory  suckers  or  areoles,   always  without  hooks  (Antho- 
bothrium,   Phyllobothrium}. 
Fam.  3.  Ichthyotceniidce.     With   four  suckers,  mostly  unarmed  (Ichthyo- 

tcBnia). 

III.  Cyclophyllidea.  Scolex  with  four  suckers,  between  which  an  apical 
rostellum  may  be  present  ;  hooks  on  the  rostellum,  rarely  on  the 
suckers  ;  segmentation  almost  always  distinct  ;  no  uterine  orifice  ; 
cirrus  and  vagina  usually  open  at  the  border  ;  genitalia  rarely  dupli- 
cated ;  vitellogene  gland  single,  usually  placed  behind  the  ovary  ;  eggs 
thin-shelled,  without  lids  ;~^oncospheres  with  one  or  several  integuments. 


BOTHRIOCEPHALOIDEA  213 

Fam.  i.  Tceniidce,  with  the  characteristics  of  the  order. 

(1)  Subf.  Mesocestoidines,    with    genital    pores    on    the    flat    surface 

(Mesocestoides}. 

(2)  „      Acolei'nce,    without    vagina,    Acoleus.    Dioecocestus    sexually 

differentiated. 

(3)  a      AmabiliincB.      Vagina  on   the    surface  ;    cirrus  situated    at 

the  border   (Amabilia). 

(4)  „       Tetrabothriinfs.       Vitellarium     in     front     of     the     ovary  ; 

suckers  with  a  muscular  process,  extending  outward  from 
the  anterior  border ;  genital  pores  at  one  side  (Tetra- 
bothrius}. 

(5)  ,,      Anoplocephalince .      Scolex  unarmed  ;  large  ;  without  neck  ; 

uterus  in  an  oblique  direction,  tubular  or  reticular  ; 
eggs  with  "  pyriform  apparatus  "  (Anoplocephala,  Bertia, 
Stilesia,  &c.). 

(6)  „      DipylidiincB.     Rostellum  armed  ;  suckers  unarmed  ;  genital 

pores  marginal  ;  genitalia  simple  or  duplicated.  Uterus 
merging  into  the  ovarian  follicle  or  becoming  atrophied  ; 
eggs  then  free  in  the  parenchyma  (Dipylidium,  Cotugnia, 
Hymenolepis,  Dilepis,  &c.) 

(7)  „      DavainemcB.      Rostellum  and  suckers  armed  ;  eggs  mostly 

encapsuled   (Davainea,   &c.). 

(8)  „       Tceniina.      With     rostellum    and    usually    double     crown 

of  hooks  ;  uterus  with  median  trunk  and  lateral  branches 
(T&nia). 

IV.  Echinobothriida.  Scolex  consisting  of  the  head  and  its  neck  ;  the  head 
has  a  rostellum  and  two  bothridia  ;  the  neck  has  longitudinal  row 
of  T-shaped  hooks  ;  genitalia  as  in  the  Tetraphyllidea.  but  with  the 
genital  pores  on  the  flat  surface  (Echinobothrium). 

V.  Rhynchobothriidcs .  Scolex  with  head  and  neck  ;  the  head  having  two 
or  four  suckers  and  four  retractile  and  armed  rostella ;  the  neck 
unarmed  (Rhynchobothrius ,  &c.). 

THE  CESTODES  OF  MAN. 

Most  of  the  species  to  be  mentioned  live  in  man  in  their  adult 
stage  and  occupy  the  small  intestine  ;  man  is  the  definitive  host 
of  these  parasites,  but  is  not  the  specific  host  for  all  the  species  ; 
some  of  these  species,  as  well  as  others  (of  mammals)  may  occur 
in  man  also  in  the  cysticercus  stage. 

A.  Bothriocephaloidea. 

Gen.  i.     Dibothriocephalus,  Lhe.,  1899. 

Syn.  :  Bothriocephalus,  p.  p.   Rud.,   1819;  Dibothrius,  p.  t>.    Rud.,    1819; 
Dibothrium,  p.  p.  Dies,  1850. 

Dibothriocephalidea  with  a  more  or  less  elongated,  unarmed  scolex, 
and  flat  suckers,  cutting  rather  deeply  into  the  head  :  neck  present  or 


214 


THE    ANIMAL   PARASITES   OF    MAN 


absent ;  single  genitals  in  each  proglottis  ;  genital  orifices  in  the  median 
line  of  the  ventral  surface,  the  cirrus  and  vagina  open  into  a  genital 
atrium  ;  the  uterus  is  behind  them ;  there  are  papillae  in  the  vicinity  of  the 
genital  atrium ;  the  testes  and  follicles  of  the  vitellaria  are  in  the  lateral 
areas,  the  former  in  the  medullary  layer,  the  latter  in  the  cortical  layer  on 
both  surfaces  and  occasionally  extending  to  the  median  line ;  the  ovary 
is  situated  ventrally,  the  shell  gland  dorsally.  The  uterus  is  in  the  central 
field  and  foifms  a  rosette.  The  eggs  are  operculated. 


i.     Dibothriocephalus  latus   (L.),  1748. 


§yn. :  Tcenia  lata,  L.,  1748  ;  T.  vulgaris,  L.,  1748  ;  T.  grisea,  Pallas,  1796  ; 
T.  membranacea,  Pall.,  1781  ;  T.  tenella,  Pall.,  1781  ;  T.  dentata,  Batsch, 
1786;  Bothriocephalus  latus,  Bren^fc,  1819;  Dibothrium  latum,  Dies.,  1850; 
Bothriocephalus  cristatus,  Davain5Br874  ;l  Both,  balticus,  Kchnmstr.,  1855  ; 
Both,  latissimus,  Bugn.,  1886. 

Length  2 — 9  m.  or  more  ;  colour  yellowish-grey  ;  after  lying 
in  water  the  lateral  areas  become  brownish,  and  the  rosette  of  the 
uterus  brown.  The  head  is  almond-shaped, 
2 — 3  mm.  in  length,  the  dorso-ventral  axis 
is  longer  than  the  transverse  diameter  ;  the 
head  therefore  generally  flat,  concealing  the 
suctorial  grooves  at  the  borders  ;  these 
suckers  are  deep  and  have  sharp  edges 
(fig.  139).  The  neck  varies  in  length  ac- 
cording to  the  degree  of  contraction  and 
is  very  thin  ;  there  are  3,000  to  4,200 
proglottides  and  there  may  be  more  ;  their 
breadth  is  usually  greater  than  their  length, 

FIG.   138. — Various   chains 
but     in     the     posterior     third     of    the    body    Of  segments  of  a  Dibothrioce- 

they    are    almost    square,     and    the    very   Phalus  latus  (natural  size)- 
oldest  are  sometimes  longer  than  they  are 

broad.  There  are  numerous  testes  situated  dorsally  and  laterally 
in  the  medullary  layer  ;  the  vas  deferens  (fig.  140)  passes  dorsally 
in  obliquely  directed  loops  in  the  central  field  towards  the  front 
and  forms  a  seminal  vesicle  before  its  entry  into  the  large  cirrus 
pouch. 

.  The  orifice  of  the  vagina  is  close  behind  the  orifice  of  the 
cirrus  pouch  ;  the  former  passes  almost  straight  along  the  median 
line  towards  the  back,  and  widens  into  a  receptaculum  seminis 

1  Until  recently  this  worm,  which  was  understood  to  belong  to  a  separate 
species,  was  proved  on  examination  by  R.  Blanchard  ("Mai.  Par.,"  1896),  to  be 
Dibothr.  latus.  Compare  also  Galli-Valerio,  in  C.  /.  B.,  P.  u.  I.  (i),  1900,  xxvii., 
p.  308. 


DIBOTHRIOCEPHALUS    LATUS 


215 


shortly  before  its  junction  with  the  oviduct;  the  vitellaria  are 
in  pairs ;  in  shape  they  resemble  the  wings  of  a  butterfly  and  they 
lie  ventrally  in  the  medullary  layer  ;  the  shell  glands  lie  in  the 
posterior  division  of  the  vitellaria  ;  the  uterus,  forming  numerous 
transversely-directed  convolutions,  passes  ventrally  from  the  vas 
deferens  towards  the  front.  Eggs  (fig.  141)  large,  with  brownish 
shells  and  small  lids  ;  0*068 — 0*071  :  0*045  mm.,  the  germinal  cells, 


FIG.  139. — Transverse 
section  of  the  head  of  Di- 
bothriocephalits  latus.  30/1. 


FIG.  141. — Egg  of  Dibo- 
thriocephalus  latus.    240/1. 


FIG.  140. — Fairly  mature  proglottis  of  Dibothrio- 
cephalus  latus.  15/1.  From  a  stained  preparation. 
The  follicles  of  the  vitellaria  are  at  the  sides ; 
the  uterus,  filled  with  eggs,  is  in  the  middle,  also 
the  vagina  (the  dark  stripe  passing  almost  straight 
from  the  front  to  the  back),  and  the  vas  deferens 
(almost  hidden  by  the  uterus)  above.  In  the  centre 
is  the  cirrus  pouch,  and  below  the  shell  gland  and 
ovary  are  seen. 


which  are  already,  as  a  rule,  in  process  of  segmentation,  are  sur- 
rounded by  numerous  large  yolk  cells  ;  the  proglottides  nearest 
the  posterior  extremity  are  frequently  eggless. 

The  eggs,  which  are  deposited  in  the  intestine  and  evacuated 
with  the  faeces,  hatch  in  water  (Schubart,  Bertolus,  Knoch)  after 
several  weeks ;  the  embryonal  integument  of  the  oncosphere  is 
provided  with  cilia  ;  after  bursting  open  the  lid  of  the  egg  the^onco- 
sphere  reaches  the  water  with  its  integument  and  swims  slowly 
about  (figs.  142  and  143)  ;  often  it  slips  out  of  its  ciliated  mem- 


2l6 


THE   ANIMAL    PARASITES    OF    MAN 


brane,  sinks  to  the  bottom  and  is  capable  of  a  creeping  motion  ; 
sooner  or  later  it  dies  in  the  water.  The  manner  and  means  of 
its  invasion  of  an  intermediary  host  is  still  unknown  ;  yet  we  are 
aware  that  the  cysticercus  stage  (plerocercoid,  fig.  144),  which 
resembles  the  scolex  and  may  reach  a  length  of  30  mm.,  lives  in 
the  intestine,  in  the  intestinal  wall,  in  the  liver,  spleen,  generative 
glands  and  muscular  system  of  various  fresh  water  fishes  (fig.  145), 
the  pike  (Esox  Indus),  the  miller's  thumb  (Lota  vulgaris),  the  perch 
(Perca  fluviatilis),  Salmo  umbla,  Trutta  vulgaris,  Tr.  lacustris,  Thymallis 
vulgaris,  Coregonus  lavaretus,  C.  albula  and  Onchorhynchus  perryi. 
The  transmission  of  the  plerocercoids  from  these  fish  to  the  dog,  cat 
and  man  (Braun,  Parona,  Grassi  and  Ferrara,  Grassi  and  Rovelli, 


FIG.  142. — Free-swimming  on  co- 
sphere  of  Dibothrincephalus  latus. 
(After  Schauinsland.) 


FIG.  143. — Free-swimming  on- 
cosphere  of  DibothyiocepJialus 
latus.  SOO/T.  Distinct  muscular 
fibres  are  seen  in  addition  to  the 
three  pairs  of  booklets.  (After 
Leuckart.) 


Ijima,  Zschokke,  Schroeder)  leads  to  the  development  of  the  broad 
tapeworm,  the  growth  of  which  is  rapid.  In  my  experiments  on 
human  beings  the  average  number  of  proglottides  formed  per  diem 
averaged  31  to  32  for  five  weeks,  with  a  length  of  8 — 9  cm.  Accord- 
ing to  Parona  the  eggs  appear  soon  after  the  man  has  been 
infected  (twenty-four  days).,  Zschokke  found  the  average  growth 
in  the  experimental  infection  of  man  between  5*2  and  8*2  cm. 
per  diem,  and  the  person  experimented  upon  by  Ijima  evacuated 
a  piece  of  a  Dibothriocephalus  latus,  22*5  cm.  in  length,  only 
twenty-one  days  after  the  infection. 

The    "  broad    tapeworm "    is    a    frequent    pajrasite    of    man    in 
some  districts,  but  it  also  occurs  in  the  domestic  dog,  and  on  rare 


DIBOTHRIOCEPHALUS    LATUS 


217 


occasions  is  found  in  the  domestic  cat  and  fox.      French  Switzerland 

and  the  Baltic  provinces  of  Russia  are  the  centres  of  distribution ; 

from   the   former   district   the   distribution   radiates   to   France   and 

Italy    (Lombardy,    Piedmont),    from    the    Baltic 

Provinces  over  Ingermanland   to    St.  Petersburg, 

over   Finland    to    Sweden    (on    the    shore  of    the 

Gulf    of     Bothnia),    in    a    southerly    direction   to 

Poland,  and  into  the  Russian  Empire  and  across 

it  to  Roumania,  and  towards  the  west  along  the 

coast  of  the  Baltic  Sea  to  the  North  Sea,  where, 

however,    its    frequency    considerably    diminishes 

(Holland,  Belgium,  and  the  North  of  France). 

In   Turkestan   and    Japan    the    "  broad    tape-     riocephaius     latus. 

,,    .      .,  f  ..          f  A.,   with  the  head 

worm      is  the  most  frequent  parasite  of  man;  it     projected ;  B.,  with 
has  been   reported   in  Africa  from  the  vicinity  of     the  head  drawn  in. 

T     .        XT,  _,     ,  (From  the  muscular 

Lake   N  garni  as  well  as  from  Madagascar;  a  case     system  of  the  pike.) 
has  also  come  under  observation  in  North  America 
(Philadelphia). 

In  Germany   Dibothriocephalus  latus — apart  from   the   fact   that 


FIG.  145. — A  piece  of  the  wall  of  the  body  of  a  Lota  vulgaris.  The  tan- 
gential section  has  laid  open  the  muscles  of  the  trunk  with  a  plerocercoid  of 
Dibothriocephalus  latus.  (Natural  size). 

it  is  undoubtedly  imported  from  Switzerland,  Russia  or  Italy — is 
particularly  frequent  in  East  Prussia  amongst  the  inhabitants  of 
the  low  coast  on  the  Baltic  at  Courland,  and  the  district  of  the 


2l8  THE    ANIMAL    PARASITES    OF    MAN 

bay  of  Courland  ;  it  is,  however,  also  found  in  the  province  and 
even  in  Konigsberg.  In  West  Prussia  and  Pomerania  it  is  very 
much  scarcer. 

It  is  also  found  in  Munich  and  in  the  vicinity  of  the  Lake  of 
Starnberg  ( Bellinger). 

Krabbe  found  it  in  10  per  cent,  of  the  sufferers  from  tape- 
worms in  Denmark ;  Szydlowski  found  the  ova  of  this  worm  in 
Dorpat  in  10  per  cent,  of  the  faeces  examined ;  Kruse  found  the 
worm  in  6  per  cent,  of  post  mortems  ;  Kessler,  in  St.  Petersburg, 
found  the  eggs  in  the  faeces  in  7*8  per  cent. ;  at  post  mortems  he 
found  the  worm  in  1*17  per  cent.,  though  Winogradoff  only  found 
it  in  0*8  per  cent.  In  Moscow,  according  to  Baranovsky,  8*9 
per  cent,  of  the  faeces  examined  contained  the  ova  of  Dihothrio- 
cephalus.  In  the  interior  and  southern  provinces  of  Sweden  the 
worm,  according  to  Lonnberg,  is  only  found  sporadically,  but,  on 
the  other  hand,  in  Angermanland  about  10  per  cent,  of  the  popula- 
tion are  affected,  while  again  in  Norbotten  the  majority  of  persons 
are  affected,  and  in  Haparanda  the  entire  population  (with  the 
exception  of  infants)  harbour  this  parasite.  In  Switzerland 
Dibothriocephalm  latus  is  very  frequent  in  close  proximity  to  the 
lakes  of  Bieler,  Neuchatel,  Morat  and  Geneva  (according  to 
Zaeslin  10 — 15 — 20  per  cent,  of  the  population  are  affected) :  the 
parasite  is  less  frequent  in  districts  one  to  four  hours  removed 
from  these  lakes. 

The  frequency  and  distribution  have,  nevertheless,  decreased 
perceptibly  in  places ;  at  the  commencement  of  the  eighteenth 
century  the  broad  tapeworm  was  very  common  in  Paris  ;  at  the 
present  date  it  only  occurs  when  imported  (Blanchard)  ;  in 
Geneva,  also,  according  to  Zschokke,  it  has  become  rarer  (formerly 
10  per  cent.,  now  only  i  per  cent.). 

The  disturbances  produced  in  man  by  the  presence  of  broad 
tapeworms  are,  as  a  rule,  very  trifling  ;  in  other  cases  they  produce 
partly  gastric  disorders  and  partly  nervous  symptoms  ;  in  a  number 
of  cases,  again,  they  set  up  severe  anaemia,1  apparently  caused  by 


1  Reyher,  D.,  Arch.  /.  klin.  Med.,  xxix.,  p.  31  ;  Rmieberg,  ibid.,  1886,  xli., 
p.  304;  Schapiro,  Zeitschr.  f.  klin.  Med.,  1889,  xiii.,  p.  416;  Podwissotzky, 
Jahrb.  f.  Kdrhlkde.,  1889,  xxix.,  p.  223;  Schaumann,  Z.  Kenntn.  d.  sog.  Bothr.- 
Ancsmie,  Berlin,  A.  Hirschwald,  1894;  Askanazy,  "  Bothr.-Ancemie  u.  d.  prog. 
Bedte.  d.  Megalobl.  im  ancem.  Blute  "  (Zeitschr.  /.  klin.  Med.,  xxiii.,  p.  492)  ; 
Babes,  V.,  "  Bothr.  lat.  u.  d.  Bothr.-An.  in  Rumanian  "  (Arch.  f.  path.  An.,  cxli., 
p.  204;  Schaumann  and  Tallquist,  "  Ueb.  d.  Blutk.  auflos.  Eigensch.  d.  b.  Bdws." 
(D.  med.  Wchschr.,  1898,  No.  20  ;  Neubecker,  O.,  Bothr.-Ancemie  ohne  Bothrioc., 
Inaug.-Diss.,  Konjgsbg.,  1898. 


DIBOTHRIOCEPHALUS    LATUS  2IQ 

toxins  produced  by  the  worms  and  absorbed  by  the  host.  There 
is  no  danger  of  auto-infection,  as  the  cysticercus  stage  lives  only 
in  fishes,  not  in  warm-blooded  animals.  The  case  reported  by 
Meschede1  (ova  of  Dibothriocephalus  latus  in  the  brain  of  a  man  who 
had  suffered  from  epilepsy  for  six  years)  is  differently  interpreted. 

Human  beings,  like  other  hosts,  can  only  acquire  the  broad 
tapeworm  by  ingesting  its  plerocercoids  with  the  previously  men* 
tioned  fresh-water  fishes;  the  opportunity  is  afforded  the  more 
readily  for  such  infection  by  the  fact  that  not  only  do  the  lower 
classes  not  pay  sufficient  attention  to  the  cooking  of  fish,  so  that 
all  the  larvae  that  are  present  may  be  killed,  but  that  in 
certain  localities  the  custom  exists  of  eating  some  parts  of  these 
fishes  in  a  raw  condition  ;  even  the  mere  handling  of  the  usually 
severely  infected  intermediary  hosts  may  occasionally  cause  infec- 
tion. This  plerocercoid  is  as  well  known  as  the  cysticercus  of  the 
pig  (Cysticercus  cellulosce)  from  which  it  differs  materially  in  appear- 
ance. In  Germany  the  occurrence  of  the  plerocercoids  of  Dibothrio- 
cephalus latus  has  been  confirmed  in  the  pike,  miller's  thumb  and 
perch  of  East  Prussia,  and  more  particularly  in  those  taken  from 
the  inland  sea  of  Courland. 

LITERATURE. 

A. — Anatomy  : — 
ESCHRICHT,    D.    F.     Anat.-phys.    Unters.    iiber    die    Bothrioceph.       (Nov.    Act.    Ac. 

Caes.   Leop.  ;  Carol,   nat.   curios.,  1841,  xix.,   Suppl.  ii.) 

STIEDA,  L.  Zur  Anat.  d.  Bothr.  latus.  (Arch.  f.  Anat.  u.  Phys.,  1864,  p.  174.) 
BOTTCHER,  A.  Stud.  iib.  d.  Ban  d.  Bothr.  latus.  (Arch.  f.  path.  Anat.,  1864, 

xxx.,   p.   97  ;    1869,   xlvii.,   p.    370.) 
SOMMER,    F.,    and   L.  LANDOIS.        Beitr.    z.  An.  d.  Plattw.    I.   B.    latus.      (Z.  f.    w. 

Zool...    1872,   xxii.,   p.   40.) 
NIEMIEC,    J.     Untersuch.    iib.    d.    Nervensyst.    d.   Cestoden.       (Arb.    a.    d.    zool.-zoot.- 

Inst.,  Wien.,    1886,  vii.,  p.    i.) 
B. — Embryonal  development  : — 
KNOCK,   J.      Die  Naturgesch.   d.  br.   Bdws.   mit   bes.   Beriicks.   sein.   Entw.     (Mem 

Ac.    d.    sc.    de    St.    Petersbourg,   1862    [7],    v.,    No.    5.) 
Journ.    de    1'anat.,    1879,    vi.,   p.    140. 
BERTOLUS.      Sur  le  devel.   du   Bothrioc.   de  1'homme.      (C.   R.   Ac.   sc.,    1863,   Ivii., 

p.   569.) 
SCHAUINSLAND,  H.      Die  embr.   Entw.  d.  Bothr.       (Jen.   Zeitschr.   f.  Naturw.,   1885, 

xix.,  p.   520.) 
C. — Infection  : — 
BRAUN,    M.      Zur   Frage    der   Zwischenwirth.    v.    Bothr.    latus.       (Zool.    Anz.,    1881, 

iv.,  p.    593:    1882,   v.,   pp.    39,   42,    194;    1883,   vi.    p.   97.) 
Bothr.   lat.   u.   seine  Herk.       (Arch.   f.   path.   Anat.,    1883,   xcii.,   p.   364.) 
Zur  Entw.   d.   br.   Bandw.   Wiirzb.   Stuber.,    1883. 
KUCHENMEISTER,    F.       Wie   steckt    sich    d.    Mensch    mit    B     lat.    an  ?     (Berl.    klin. 

Wchschr.,    1885,  xxii.,  pp.    505,    527.) 
BRAUN,  M.      Salm  oder  Hecht  ?     (Ibid.,  p.   807.) 


1  Meschede,.  Tagebl.  der  45   Versammlung  der  Naturf.   u.   Aerzte  in  Leipzig,  1872, 
p.  186  ;  Arch.  /.  Psych.,  ii.,  p.  501  :  Allgem.  Zeitschr.  f.  Psych.,  xxx?,  p.  109. 


22O  THE   ANIMAL   PARASITES   OF   MAN 

KUCHENMEISTER,    F.     Die    Finne    des    Bothr.    u.    seine    Uebertr.    auf    d.    Mensch., 

Lpzg.,    1886. 
Weit.   Bestat.   m.   Behauptg.,   die  Finne  des   Hechts  hat  nichts  mit  Bothr.   lat. 

zu   thun.      (D.   nied.   Wochenschr.,    1886,   p.    551.) 

PARONA,   E.      II  B.  lat.  in  Lomb.      (Rend.   R.  1st.  Lomb.,    1886  [2],  xix.,  No.   14.) 
BRAUN,    M.      Ueb.    d.    Zwischenw.    d.    br.    Bdws.,    eine    Entgegnung    an    Kiichen- 

meister.  Wiirzb.,   Stuber.,    1886. 
GRASSI,    B.,    and    FERRARA.        Zur    Bothriocephalusfrage.       (D.    med.    Wochenschr., 

1886,    p.    699.) 

LEUCKART,  R.  Z.     Bothriocephalusfrage   (C.   f.  B.    u.    P.    I.,   1887,  pp.    i,   33). 
PARONA,    E.      Sulla   quest,    d.    B.    lat.      (Gazz.    med.    ital.-lomb.,    1887.) 
GRASSI,    B.,    and    G.    ROVELLI.      Contr.    all.    stud.    d.    svil.    d.    Bothr.    I.      (Giorn 

R.   Ace.   med.,    1887,   No.    n.) 
GRASSI,    B.,    and    G.    ROVELLI.      Bandwurmerentw.      (C.    f.    B.    u.    P.,    1888,    iii., 

?•    I73-) 
IJIMA,    J.     The    Source    of    B.    latus    in    Japan.      (Journ.    Coll.    Sc.    Imp.    Univ., 

Tokyo,    1888,    ii.,    [i]   p.    49.) 
ZSCHOKKE,   F.      Weit.   Zwischenw.   d.   B.   lat.       (C.   f.   B.   u.    P.,    1888,   iv.,   p.   417.) 

L6NNBERG,    E.         C.    f.    B.    U.    P.,     1892,    XI.,    p.     189. 

SCHROEDER,   A.    v.      Wie   bek.   d.    Einw.    St.   Petersb.    d.    br.    Bdw.  ?     (St.    Petersb. 

Med.   Wochenschr.,    1892,   xvii.,   No.    22.) 

BRAUN,  M.     Bothr.-Finnen  im  Hecht  d.  St.  Petersb.  Fischmarktes.     (Ibid.,  No.  28.) 
SCHROEDER,     A.    v.      Wratsch.,     1894     No.     12;     1895,     No.     15;     Jesched.     Journ. 

Prakt.    Med.,    1896,    Nos.    19    and    27    (Russ.-Ref.    in    C.    f.    B.    u.    P.,    xvi., 

p.    314  ;   xviii.,  p.    24,   and  xx.,  p.   621.) 


2.     Dibothriocephalus  cordatus  (R.  Leuck.),  1863. 
Syn.  :  Bothriocephalus  cordatus,    R.   Leuck. 

Length,  80 — 115  cm.  ;  the  head  is  heart-shaped  and  measures 
2  mm.  by  2  mm.  The  suctorial  grooves  are  on  the  flat  surface  ; 
the  segments  commence  close  behind  the  head  and  increase  rapidly 

in  breadth.  At  only  3  cm.  behind  the  head 
they  are  already  adult  ;  the  greatest  breadth 
attained  by  them  averages  7 — 8  mm.,  the 
length  3 — 4  mm. ;  the  number  of  proglot- 
tides  averages  600  ;  the  most  posterior  ones 
are  usually  square.  The  rosette  of  the  uterus 
is  generally  formed  of  six  to  eight  lateral 
loops-  The  eggs  are  provided  with  lids  and 
datus ;  on  the  left  viewed  measure  0*075  mm.  in  length  by  0*05  mm. 

sideways,     on     the     right       .       -,  ,,-, 

from    the  dorsal    surface.       m    Dreadtn. 

(After  Leuckart.)  Dibothriocephalus    cordatus    is    a    common 

parasite    of    the    seal,    the    walrus    and    the 

dog    in    Greenland  and    Iceland,    occasionally  of    man   also.       No 
doubt  its  larva  lives  in  fishes.1 

The  statement  that  Dib.  cordatus  also  occurs  in  Dorpat  in  human  beings 
has  been  proved  erroneous  (Zool.  Anzg.,  1882,  v.,  p.  46),  as  also  has  the 
report  that  this  worm  lives  in  hares  in  the  neighbourhood  of  Berlin, 

1  Leuckart,  R.,  "  Die  menschl  Paras.,"  1863,  I.,  p.  437. 


DIPLOGONOPORUS     GRANDIS 


221 


whither   it  was  supposed    to   have  been   carried   by  Esquimaux  dogs   (Rosen- 
kranz  in  Deutsch.  med.   Wchnschr.,   1877,    iii.,  p.  620).      The  parasite  stated 
y  the  author  to  be  Dib.  cordatus,  is  Tcenia  pectinata,  Goeze,  which  has  been 
known   since    1766. 


Gen.  2.     Diplogonoporus,  Lonnbrg.,  1892. 

Syn. :  Krabbea,  R.  Blanch,  1894. — The  scolex  is  short  and  has  powerful 
uctorial  grooves  ;  no  neck  ;  the  proglottides  are  short  and  broad  ;  there  are 
wo  sets  of  genital  organs  side  by  side  in  each  segment,  which  in  all  essentials 
resemble  the  single  one. of  Dibothriocephalus. 

[The  genera  Diplogonoporus  and  Krabbea  are  distinct ;  the 
uterus  opens  dorsally  in  the  former,  ventrally  in  the  latter.— 
F.  V.  T.] 

Diplogonoporus  grandis,  R.  Blanch.,  1894. 
Syn. :  Bothriocephalus,  sp.,  Ijima  et  Kurimoto,  1894  ;  Krabbea  grandis,  R.  Bl. 

Scolex  unknown  ;  chain  of  proglottides  over  10  m.  in  length. 
1*5  mm.  broad  in  front,  2*5  mm.  broad  at  the  back.  The  pro- 
glottides are  very  short  (0-45  mm.),  but  broad.  On  either  side 
to  the  right  and  left  of  the  worm,  along  the  entire  ventral  sur- 


FIG.  147. — A  segment 
of  Diplogonoporus 
grandis  (natural  size). 
(After  Kurimoto.) 


FIG.  148. — Genitalia  of  Diplogonoporus  grandis.  Above 
the  cirrus  pouch,  to  the  left,  vas  delerens  (dotted)  ; 
below,  the  vagina  (light)  ;  the  uterus  (dark)  ;  ovary 
(black).  (After  Kurimoto.)  150/1. 


face,  there  is  a  longitudinal  groove  ;  these  grooves  are  nearer  to 
each  other  than  to  the  lateral  margin  ; .  in  them  lie  the  genital 
pores,  and  they  are  in  the  same  sequence  as  in  Dibothriocephalus ; 
the  ovary  is  only  developed  transversely  ;  the  uterus  only  makes 
a  few  loops.  Eggs  (fig.  129)  thick-shelled,  brown,  0-063  : 0-048 
— 0*05  mm.  This  parasite  has  hitherto  been  observed  twice  in 
Japanese.  Similar  species  are  known  in  cetacea  and  seals. 


222  THE   ANIMAL   PARASITES   OF   MAN 

LITERATURE. 

IJIMA,   J.,   and   T.    KURIMOTO.      On   a  New  Hum.    Tape-Worm.      (Journ.   Coll.    So. 

Imp.   Univ.,  Tokyo,    1894,  vi.,  p.    371.) 
BLANCHARD,  R.      Not.  sur  les  par.   de  I'homme,  iv.      (C.   R.  soc.  biol.,   Paris  [10], 

i.,    1894,   p.    699). 
KURIMOTO,   T.     Diplog.    grandis.     (Ztsch.  f.  klin.  Med.,  1900,  xl.,  p.  i.) 

Bothriocephalus  mansoni,  Cobb.,  1883. 

Syn.  :   Ligula  mansoni,  Cobbold,  1883  ;  Bothriocephalus  liguloides, 
R.  Leuck.,  1886. 

Plerocercoids    of    Bothriocephalite    living    between    the    tissues 
and    organs    of    various    vertebrate    animals  ;    the    adult    stage    to 
which   they   give   rise   is   unknown,    and   they   cannot   therefore   be 
assigned  to  a  definite  genus.      These  plerocercoids  were  discovered 
in    1882    by  P.  Manson  during  the  post  mortem  on 
a   Chinaman  who  had  died  in  Amoy,  twelve   speci- 
mens being  found  beneath  the  peritoneum  and  one 
free    in   the    abdominal    cavity.      Cobbold   described 
them    as  Ligula    mansoni,   and   Leuckart,  who    con- 
temporaneously reported   a  case  in    Japan,    termed 
them  Bothriocephalus  liguloides.      Ijima  and  Murata 
reported  eight  further  cases. 

The  plerocercoid,  which  hitherto  alone  is  known 

1*  IG.    149-  — 

Cephalic  end  of      to    us,  attains  a  length  of  30  cm.  and   a  breadth  of 


3_6_i2  mm.  The  ribbon-shaped  body  is  wrinkled, 
Leuckart.)  the  lateral  borders  are  often  somewhat  thickened, 

so  that  the  transverse  section  has  the  form  of  a 
biscuit  ;  the  anterior  end  is  usually  wider  and  carries  a  retractile 
head,  provided  with  two  weak  suctorial  grooves. 

The  parasite  makes  migrations  within  the  body,  and  thus  may 
reach  the  urinary  passages  ;  then  it  is  either  evacuated  with  the 
urine  or  has  to  be  removed  from  the  urethra  ;  not  rarely  it 
causes  excrescences  on  various  parts  of  the  skin,  when  this  takes 
place  it  has  to  be  removed  by  an  operation. 

Nothing  is  known  of  its  development  and  origin. 

LITERATURE. 

MANSON,    P.      Case   of   Lymph    Scrotum   Assoc.    with   Filar,    and    other   Par.     (The 

Lancet,   1882,  ii.,  p.  616.) 
COBBOLD,    T.    SP.     Descr.    of  Ligula   mans.      (Linn.    soc.    Journ.    Zool.,    1883,    xvii., 

p.  78.)     Lond. 
LEUCKART,   R.     Demonst.    ein.    selt.   menschl.   Entoz.      (Tagebl.    57.   Vers.    D.   Nat. 

u.  Aerzte  zu  Magdeburg,   1884,  p.   321.) 
Die  Paras,   d.   Mensch.       2nd  edit.,  i.,  p.   941. 
IJIMA    and   MURATA.      Some    New    Cas.    of    the    Occ.    of    Bothr.    ligul.      (Journ.    sc. 

Coll.  Imp.  Univ.,  ii.,    1888,  Tokio,  p.    149.) 


DIPYLIDIUM    CANINUM 


223 


B.     Tceniidcz. 

Gen.  3.     Dipylidium,  R.  Leuck.,  1863. 

Rostellum  retractile  with  -several  rings  of  alternating  hooks,  the  latter 
usually  have  a  disc-like  basis.  Suckers  unarmed.  Genital  pores  prominent : 
genitalia  duplicated.  Testes  very  numerous  in  the  central  field ;  ovary 
with  two  lobes ;  the  vitellaria,  which  are  smaller,  lie  behind  ;  the 
uterus  forms  a  reticulum  in  the  network  of  which  the  testicular  vesicles 
lie  ;  later  on  it  forms  into  one  or  several  sacs  enclosing  eggs.  The  eggs 
lave  a  double  shell. 

Dipylidium  caninum  (L.),  1758. 

Syn.  :  Tcenia  canina,  L.,  1758,  p.  p ;  T.  moniliformis ,  Pallas,  1781  ;  T,  cucu- 
merina,  Bloch,  1782;  T.  elliptica,  Batsch,  1786;  Dipylidium  cucumerinum, 
Leuck.,  1863. 

This  worm  measures  15 — 35  cm.  in  length  and  1*5 — 3  mm.  in 
breadth.  The  scolex  is  small,  rhomboidal,  and  has  a  club-shaped 
rostellum  on  which  there  are  three  „ 

to  four  rings  which  carry  from 
forty-eight  to  sixty  hooks  resem- 
bling rose-thorns,  the  size  of  the 
foremost  of  which  varies  from  O'Oii 
-i-o<oi5,  and  the  posterior  ones 
average  O'Oo6  mm.  The  neck  is 
very  short,  the  most  anterior  seg- 
ments broad  and  short,  the  middle 
as  long  as  they  are  broad,  the 
mature  segments  are  longer  than 
wide  (6 — 7  :  2 — 3  mm.)  fairly  thick, 
are  frequently  of  a  reddish  colour, 
and  when  cast  off  resemble  cu- 
cumber seeds.  The  genital  pores 
lie  symmetrically  at  the  lateral 
borders  ;  the  roundish  ovarian  fol- 
licles arising  from  the  reticulum 
of  the  uterus  contain  eight  to 
fifteen  eggs  packed  in  a  reddish 
mass.  The  eggs  are  globular  (0-043 
—0-050  mm.) ;  the  embryonal  shell 
is  thin,  the  oncosphere  measures 
0-032 — 0-036  mm. 

Dipylidium  caninum  is  a  common    intestinal    parasite  of    dogs, 


FIG.  150.  —  Dipylidium  caninum. 
(After  Diamare.)  On  the  left,  the 
scolex  and  the  first  proglottides  ;  on 
the  right,  at  the  top,  a  packet  of 
ova  ;  below,  hooks  of  the  rostellum, 
side  and  front  views ;  below,  an  ovum. 
(Various  enlargements.) 


224 


THE   ANIMAL   PARASITES   OF   MAN 


c.p.i 


FIG.  151. — Dipylidium  caninum.  Central  portion  of  a  pro- 
glottis  (magnified).  (After  Neumann  and  Railliet.)  C.p.,  cirrus 
pouch ;  V.s.,  vitellaria ;  Ex.v.,  excretory  vessels ;  T.,  tes- 
ticular  vesicles  ;  O.,  ovary ;  U.,  reticulum  of  uterus  ;  V.,  vagina. 


in  which   it  grows    larger  (Tcenia  cucumerina,  Bloch)    than    in    cats 

(T.    elliptica, 
Batsch)  ;  it  has, 
however,      also 
been    found    in 
jackals,  as  well 
as     in     human 
beings,    though 
in  the  latter  it  is 
of  comparative- 
ly   rare    occur- 
rence   (twenty- 
four  cases),  and 
almost     always 
affects  children, 
generally  of  ten- 
der  age.     Only 
one  case  affect- 
ing an  adult  is  known.      The 
proglot tides,  which  leave   the 
intestine    spontaneously,    are 
recognisable     by    the     naked 
eye  on  account  of  their  form 
and    colour,  as  well  as  their 
two  genital  pores.     As  a  rule, 
the  presence  of  this  parasite 
sets  up  no  marked  symptom 
in  the  patient. 

The  corresponding  cysti- 
cercoid  lives  in  the  louse  of 
the  dog  (Trichodectes  canis), 
a  fact  that  was  first  esta- 
blished by  Melnikow  and 
Leuckart  ;  according  to  Grassi 
and  Rovelli,  as  well  as  Son- 
sino,  it  also  lives  in  the  flea 
of  the  dog  (Pulex  serraticeps) 
and  in  the  flea  of  man 
(Pulex  irritans),  but  not  in 
its  larva.  The  adult  seg- 
ments, which  leave  the  rec- 
tum of  the  dogs  and  cats  spontaneously,  creep  about  around  the 


FIG.   152. — Cysticercoid  of  Dipylidium  can- 
inum (enlarged).  (After  Grassi  and  Rovelli.) 


HYMENOLEPIS  225 

anus  and  get  into  the  fur,  and  are  thus  transmitted  by  their  hosts. 
Part  of  the  segments,  or  the  oncospheres  released  by  disintegration, 
are  then  taken  up  by  the  lice  and  fleas,  within  which  they  develop 
into  cysticercoids.  Dogs  and  cats  are  thus  infected  by  their  own 
skin-parasites,  which  they  bite  and  swallow  whilst  gnawing  at  their 
fur.  The  infection  of  human  beings  must  occur  in  an  analogous 
manner,  by  transmission  of  the  cysticercoids  present  on  the  lips  or 
tongue  of  dogs  when  licking  them,  or  it  may  be  that  the  vermin  of 
cats  and  dogs  harbouring  cysticercoids  infect  human  beings  direct. 

LITERATURE. 

LEUCKART,   R.      D.   menschl.   Paras.,    1863,  i.,  p.  400. 

STEUDENER,  F.      Unters.   iib.  d.   fein.   Bau  d.  Cest.      (Abh.  nat.   Ges.  Halle,     1877, 

xiii.,   p.   295.) 
DIAMARE,   V.       II   genere   Dipylidium.     (Atti   R.   Ace.    sc.   fis.   e  mat.  Napoli.,    1893, 

ii.,  Ser.   2,  No.  7.) 
MELNIKOW,    W.      Ueb.    d.    Jugendzust.    d.    T.    cucum.      (Arch.    f.    Naturg.,    1869, 

xxxv.,    i.,    p.    62.) 
GRASSI,    B.,    and    G.    ROVELLI.      Embr.    Forsch.    a.    Cest.      (C.    f.    B.    u.    P.,    1889, 

v.,  p.    370.) 
Ric.   embryol.   sui  Cest.      (Atti  Accad.   Gioen.   sc.   nat.   Catania.,    1892,   Ser.   4, 

vol.   iv. )  , 

SONSINO,   P.      Ric.   s.   ematoz.   del  cane  e  sul  ciclo  evol.   d.   T.   cucum.      (Att.   soc. 

tosc.  sc.  nat.,   1888,  x.,  p.   i.) 
SALZMANN.      Ueb.    d.    York.    d.    T.    cue.    i.    Mensch.      (Jhrshfte.    d.    Ver.    f.    vaterl. 

Naturkde.  Wiirtt.,   1861,  xvii.,  p.   102.) 
HOFFMANN,  A.      Taen.  cue.  b.   ein.  4  Monate  alten  Kinde.      (Jahrb.   f.  Kinderhlkde, 

N.  F.,   1887,  xxvi.) 

KRUGER,  F.      St.   Pet.  med.  Wchschr.,    1887,  No.  41. 

BRANDT,    ED.      2   Falle   v.    T.    cue.    b.    Mensch.     (Zool.    Anzgr.,    1888,    xi.,   p.    481.) 
TRIIS.      Nord.   med.   Arkiv.,    1884,   xvi.,   No.   6. 
BLANCHARD,    R.      Trait.    Zool.    med.,    1889,    i.,    p.    481  ;    and    Mai.    Paras.,    1895, 

p.    718. 

Gen.  4.     Hymenolepis,  Weinland,  1858. 

The  scolex  is  small ;  rostellum  armed ;  suckers  unarmed  ;  the  neck  is 
long  ;  the  breadth  of  the  segments  is  greater  than  their  length.  The 
genital  pores  He  all  on  the  left.  Three  testes  in  each  proglottis.  The  mature 
uterus  fills  the  entire  segment ;  the  eggs  are  round  or  oval  with  three 
distinct  envelopes.  Found  in  mammals  and  birds. 

The  genus  -has  recently  been  divided  into  two  sub-genera — Hymenolepis, 
s.  str.,  and  Drepanidotcenia,  Raill. 

[The  following  are  the  characters  of  the  two  genera,  Hymeno- 
lepis, Weinland,  1858,  and  Drepanidotcenia,  Railliet,  1892.] 

Genus  Hymenolepis,  Weinland,  1858  (Diplacanthus,  Weinland, 
1858  [nee  L.  Agassiz]). 

Head  small,  provided  with  retractile  rostellum,  well  developed  and  armed 
with  a  single  crown  of  24  to  30  hooks,  or  rudimentary  or  unarmed.  Neck 
long.  Segments  serrated,  longer  than  broad,  seldom  less  than  150  in 

15 


226  THE   ANIMAL   PARASITES   OF   MAN 

number.  Genital  pores  marginal,  on  left  side  ;  the  female  surface  ventral. 
Testes  few,  generally  three  in  each  segment — one  left  and  two  right  of  the 
median  line.  Eggs  with  three  separate  shells  ;  inner  shell  with  a  small 
knot  at  each  pole.  The  larva  a  Crytocystis  or  Staphylocystis.  Intermediate 
host  insect  or  myriapod.  Weinland  proposed  this  with  Tcenia  ftauopunctata 
as  type,  which  is  the  same  as  diminuta. 


Genus  Drepanidotcenia,  Railliet,  1892. 

Head  provided  with  a  single  row  of  uniform  hooks,  few  (8  to  20)  in 
number,  with  dorsal  root  much  longer  than  ventral  root,  the  latter  always 
small,  with  prong  directed  posteriorly  when  the  rostellum  contracts.  Larval 
stage  found  in  small  crustaceans. 

The  two  genera  thus  differ  in  having  the  dorsal  root  of  the 
hooks  much  longer  than  the  ventral  or  prong  in  Drepanidotcenia, 
and  the  hooks  few  in  number  ;  the  hooks  are  similarly  formed  in 
Hymenolepis,  but  when  present  vary  from  24  to  30. 

A  third  genus  is  closely  related,  Dicranotcznia,  Railliet,  1892, 
which  has  the  dorsal  root  of  hooks  shorter  than  the  ventral  root 
or  prong.  The  two  latter  only  are  known  in  birds. — F.  V.  T.] 


I.     Hymenolepis  nana  (v.  Sieb.),  1852. 

Syn. :  Tcenia  nana,  v.  Sieb.,  1852  (nee  van  Beneden,  1867);  T.  cegyptiaca, 
Bilh.,  1852  ;  Diplacanthus  nanus,  Weinld.,  1858  ;  T.  (Hymenolepis)  nana,  Lckt., 
1863. 

The  worm  is  10 — 15  mm.  in  length  and  0*5 — 0*7  mm.  in  breadth ; 
the  head  is  globular,  0*25 — 0*30  mm.  in  diameter.  The  rostellum 
has  a  simple  crown  consisting  of  twenty-four  or  twenty-eight  to 
thirty  hooks,  which  are  only  0*014 — 0*0 18  mm.  in  length.  The  neck 
is  moderately  long  ;  the  proglottides  are  very  narrow,  about  150 
in  number,  0*4 — 0*9  mm.  in  breadth,  and  0*014 — 0*030  mm.  in  length. 
The  eggs  are  globular  or  oval,  0*030 — 0*037 — 0*048  mm. ;  the  onco- 
spheres  measure  0*016 — 0*019  mm.  in  diameter. 

This  species  was  discovered  by  Bilharz  in  Cairo,  in  1851  ;  it 
was  found  by  him  in  great  numbers  in  the  intestine  of  a  boy 
who  had  died  of  meningitis.  For  several  years  this  was  the  only 
case,  until  1885,  since  when  numerous  cases  have  come  to  light. 
Spooner,  1873,  even  reported  a  case  from  North  America,  which 
may,  however,  have  related  to  Hymenolepis  diminuta.  In  Europe 
the  worm  is  particularly  frequent  in  Sicily,  but  it  has  also  been 
repeatedly  observed  in  North  Italy ;  it  has,  moreover,  been 


HYMENOLEPIS    NANA 


227 


reported  from  Russia,  Servia,  England,  France,  Germany,  South 
America,  Siam  and  Japan.  Notwithstanding  its  small  size  this 
worm  causes  considerable  disorders  in  its  hosts — mostly  children — 
as  it  sets  up  loss  of  appetite,  diarrhoea,  various  nervous  disturb- 
ances, and  even  epilepsy  ;  all  these  symptoms,  however,  disappear 


FIG.  153. — Hy- 
menolepis nana  (v. 
Sieb.),  about  12/1. 
(After  Leuckart.) 


FIG.  154.  —  Head  of  Hyme- 
nolepis  nana,  with  rosteilum 
retracted.  100/1.  (a)  A  single 
hook.  600/1.  (After  Leuckart.) 
(6)  An  egg,  highly  magnified. 
(After  Grassi.) 


II  rl  •&&?£:? 

V^"-*£s&:i'i 

*<,/.V:-V/vv.W 


FIG.  155. — Longitudinal 
section  through  the  intes- 
tinal villus  of  a  rat,  with 
the  cysticercoid  of  Hyme- 
nolepis  murina( magnified). 
(After  Grassi  and  Rovelli.) 


after  the  expulsion  of  the  parasites,  which  are  generally  present  in 
large  numbers. 

The  development  as  well  as  the  manner  of  infection  is  still 
unknown  ;  Grassi  certainly  is  of  opinion  that  Hymenolepis  nana  is 
merely  a  variety  of  Hym.  murina  (Duj.)  which  lives  in  rats. 
According  to  Grassi  direct  development  takes  place  by  means  of 
the  omission  of  the  intermediary  host,  but  with  the  retention  of 
the  cysticercus  stage,  that  is  to  say,  rats  infect  themselves  with 
Hymenolepis  murina  direct,  by  ingesting  the  mature  segments  or 


228  THE   ANIMAL   PARASITES    OF   MAN 

oncospheres  of  this  species,  from  which  subsequently  the  small 
cysticerci  originate  in  the  intestinal  wall  (fig.  155)  ;  when  fully 
developed  they  fall  into  the  intestinal  lumen  and  become  tape- 
worms. The  identity  of  the  two  forms  has  nevertheless  been 
disputed  (Moniez,  R.  Blanchard,  v.  Linstow),  though  their  near 
relationship  cannot  be  denied.  Grassi  gave  mature  segments  of 
Hymenolepis  murina  to  six  persons,  but  only  one  person  evacuated 
a  tapeworm.  This,  however,  proves  nothing  in  a  district  where 
Hymenolepis  nana  frequently  occurs  in  man  ;  it  was,  moreover, 
not  possible  to  infect  rats  with  segments  of  Hymenolepis  nana  (of 
man).  Accordingly  this  form  may  represent  an  independent  species, 
which,  however,  like  Hymenolepis  murina,  also  omits  an  inter- 
mediary host. 

[Stiles    and    others    state    that    the    intermediate    hosts    of    the 
Hymenolepis  are  insects  and  Myriapoda. — F.  V.  T.] 

I"  LITERATURE. 

SIEBOLD,  C.  TH.  v.  Ein  Beitr.   z.  Helm.  hum.     (Z.   f.   w.   Zool.,    1852,  iv.,  p.   64.) 
SPOONER,   E.    A.     Spec,   of  T.   nana.     (Am.    Journ.   med.    sc.,    1873,   Ixv.,   p.    136.) 
GRASSI,    B.     Die  T.   nana  u.   ihre   med.    Bedtg.     (C.    f.    B.    u.    P.    I.,    1887,   P-    97-) 
Einig.   weit.   Nachr.    ub.   T.   nana.     (Ibid.,    1887,   ii.,   p.    282.) 
Entw.   d.   T.   nana.     (Ibid.,   p.    305.) 
Cenno  prev.   int.   ad   una   nuov.    mal.    par.    nell'    uomo.     (Gazz.    d.    osp.,    1886, 

pp.   450,   619.) 
COMINI,   E.     Epilessia  rifl.    da  T.   nana.     (Gazz.    d.    osp.,    1887,   viii.,   p.    174.) 

Due  casi  d.  T.  nana.     (Gazz.  med.  ital.-lomb.,   1888,  p.  81.) 

PERRONCITO,  E.  Caso  di  T.  nana.  (Giorn.  R.  Ace.  med.,  Torino,  1887,  xxxv.,  p.  7. 
PERRONCITO,  E.  ,and  P.  AIROLDI.  Caso  di  T.  medioc.  e  di  molte  T.  nan.  (Ibid., 

1888,  xxxvi.,  p.    312;   Gazz.   d.  osp.,    1888,  p.    554.) 
SENNA.     Stor.   clin.  di  sei  casi  d.  T.  nana.     (Gazz.  med.  ital.  Lomb.,  1889,  xlviii., 

Ser.  9,  vol.  ii,  pp.   245,  255,   265.) 
ORSI,  F.     Sei  casi  d.  T.  nana.     (Ibid.,  p.   235.) 
SONSINO,   P.     Tre  casi  di  T.  nana  nei  dint,   di  Pisa.     (Riv.   ital.   clin.   med.,    1891, 

iii.) 
RANSOM,  ^W.  H.     Prob.  exist,  of  T.  nana     ...     in  Engl.     (The  Lancet,  1888,  ii.) 

Nuov.  oss.  di  T.  nana.     (Boll.  soc.  med.   Pisa.,   1895,  i-»  P-  4-) 
ZOGRAF,  N.      Note  sur  la  myol.  d.  Cest.  Congr.  intern,  d.  Zool.,  lie  sess.,  Moscou, 

2nd    part,    p.    23. 
WERNICKE,   O.     Tsenia  nana.     (Anal.    circ.    med.    argent.,    1800,   xiii.,   p.    349.) 

C.  R.   soc.  biol.,  Paris,    1891,   [9],  iii.,  p.  441   [Blanchard]. 
LUTZ,    A.     Beob.    lib.    d.    als    T.    nana    u.    T.    flavop.    bek.    Bandw.    d.    Mensch. 

(C.  f.  B.  u.  P.,   1894,  xvi.,  p.  6 1.) 
MERTENS.     Berl.   klin.  Wchschr.,    1892,   Nos.   44,   45. 
ROEDER,  H.     Ueb.  ein.  weit.  Fall  v.  T.  nana  i.  Deutschl.     (Munch,  med.  Wchschr., 

1899,  p.   344.) 

RASCH,   CHR.   T.   nana  in   Siam.     (D.   med.    Ztg.,    1895,   P-    X43-) 
MIURA,   K.,  and  YAMAZAKI.     Ueb.  T.  nana.     (Mitth.   med.  Fac.   Kais.  Univ.  Tokio, 

1897,   iii-»   P-    239-) 

MONIEZ,   R.     Sur  la  T.   nana.     (C.   R.   Ac.   sc.   Paris.,    1888,   cvi.,   p.    368.) 
BLANCHARD,   R.     Hist.   zool.   et   med.   d.   Teniad.   du   genre   Hymenol.,   Paris,    1891. 
LINSTOW,    v.     Ueb.    T.    nana    u.    T.    murina.     (Zeitschr.    f.    d.    ges.    Naturw.,    1896, 

P-    571-) 

GRASSI,    B.,    and   G.    ROVELLI.     Ric.   embr.    sui  Cestodi.     (Atti  Ace.  Giern.  sc.  nat., 
Catania,    1892,  Ser.  4,  vol.  iv.) 


HYMENOLEPIS    DIMINUTA 


229 


2.     Hymenolepis  diminuta,  Rud.,  1819. 

Syn. :  Tcenia  diminuta,  Rud.,  1819;  T.  leptocephala,  Crepl.,  1825; 
T.  ftavopunctata,  Weinld.,  1858;  T.  varesina,  E.  Parona,  1884;  7\  minima, 
Grassi,  1886. 

This  species  measures  20 — 60  cm.  in  length,  and  up  to  3-5  mm.  in 
breadth  ;  there  are  from  600  to  1,000  segments.  The  head  is  very 
small  (o'2 — 0*5  mm.)  ;  it  is  club-shaped  and  has 
a  rudimentary  unarmed  rostellum ;  the  neck  is 
short  ;  the  mature  segments  are  3-5  mm.  in 
breadth,  o'66  mm.  in  length;  the  eggs  are  round 
or  oval  (0-060 — 0-070  :  0*070 — 0*086  mm.).  The 
egg-shell  is  yellowish  and  thickened,  with  indis- 
tinct radial  stripes  ;  embryonal  shell  double,  thin  ; 
the  outer  one  is  somewhat  pointed  at  the  poles  ; 
oncosphere  0^028 — 0^036  mm. 

Hymenolepis  diminuta  lives  in  the  intestine  of 
rats  and  mice  :  Mus  decumanus,*  the  sewer  rat ; 
M.  rattus,  the  house  rat,  M.  musculus,  the  mouse, 
and  M .  alexandrinus  ;  it  is  occasionally  also  found 
in  human  beings. 

Weinland  described  it  from  specimens  col- 
lected by  Dr=  E.  Palmer  in  1842,  in  Boston, 
from  a  child  aged  19  months,  as  T.  flavopunctata. 
A  second  case  was  only  reported  in  1889  by 
Leidy  relating  to  a  three-year-old  child  from  Phil- 
adelphia ;  a  third  case  was  simultaneously  reported  of  a  two-year- 
old  girl  in  Varese  (T.  varesina),  and  Grassi  described  another  case 


FIG.  156.  —Hy- 
menolepis diminuta, 
scolex  magnified. 
(After  Zschokke.) 


FIG.  157. — Hymenolepis  diminuta  ;  two  pro- 
glottides  slightly  enlarged.     (After  Grassi.) 


FIG.  158. — Ovum  of  Hymeno- 
lepis diminuta ',  greatly  magni^ 
fied.  (After  Grassi:) 


relating  to  a  twelve-year-old  girl  from  Catania  (Sicily).  Sonsino 
and  Previtera  reported  the  same  species  in  Italy,  Zschokke  in 
France,  Lutz  and  Magalhaes  in  South  America,  and  Pachard  in 
North  America. 

According  to  Grassi  and  Rovelli  the  cysticercus  stage  lives  in 


230  THE   ANIMAL  PARASITES   OF  MAN 

a  small^  moth  \Asopia  farinalis),  as  well  as  in  its  larva,  in  an 
orthopteron  (Anisolabis  annulipes),  and  in  coleoptera  (A cis  spinosa 
and  Scaurus  striatus).  Experimental  infections  have  been  successful 
on  rats  as  well  as  on  human  beings.  In  America  other  species 
of  insects  may  be  the  intermediary  hosts. 

LITERATURE. 

RUDOLFHI,  C.  A.     Entoz.  syn.  Berol.,   1819,  p.  689. 
CREPLIN,   F.   C.   H.     Obs.   de  entoz.,  i.,   Gryph,    1825,   p.   71. 

WEINLAND,   D.   F.     An  Essay  on  Tape-worms  of  Man.     Cambridge,  U.   G.,    1858. 
Beschreibung    zweier    neuen    Taenoiden    an    d.    Menschen.     (Nov.    Act.    Acad. 

Caes.   Leop. -Carol.,    1861,   xxviii.) 
LEIDY,    J.     Occur,   of  a  rare  hum.  Tapew.     (Amer.    Journ.   of  Med.   Sc.   [2],   1884, 

Ixxxiii.,    p.    no;    Proc.    Ac.    nat.    Sc.,    Philad.,    1884,    p.    137.) 
PARONA,    E.     Du   un   caso   di   T.    flavop.    rise,    in    una   bambina   di  Varese.     (Gior. 

R.    Ace.    med.,   Torino,    1882,   xxxii.,    p.    99.) 
GRASSI,    B.     Bestimmg.    d.    4   von   Parona     .     .     .     gef.    Taenien.     (C.    f.    B.    u.    P., 

1887,  i.,  p.   257.) 

T.  flavop.,   leptoc.,   diminuta.     (Atti.  R.  Ace.   sc.,   Torino,    1888,   xxiii.,  p.  492.) 
SONSINO,    P.     Su    par.    dell'    uomo    con    un    nuovo    caso    di    T.    flavop.     (C.    f.    B., 

P.  u.  I.,   1896  [i],  xix.,  p.  937.) 
PREVITERA,    G.     Due   casi   prob.    di   T.    leptoc.    nei    minat.    d.    zolfare.     (Boll.    Ace. 

Gioen.    sc.    nat.,    N.    S.,    1900,    No.    63,    Catania,    p.    9.) 

ZSCHOKKE,   F.     Seltene   Par.    d.   Menschen.     (C.    f.    B.    u".    P.,    1892,    xii.,   p.   497.) 
LUTZ,   A.     Beobacht.   iib.   d.   als  T.   nana  u.   flavop.   bek.   Bdw.   d.   Mensch.     (Ibid., 

1894,   xiv.,  p.   61.) 
MAGALHAES,    P.    G.    de.     Ein    zweit.    Fall    v.    Hym.    dimin.    als    menschl.    Paras,    in 

Brasil.   beob.     (Ibid.,    1896   [i~|,   xx.,   p.   673".) 
PACKARD,    F.    A.     T.    flavop.,    with    descr.    of    a    new    Specim.     (Journ.    Am.    med. 

Ass.,    1900,  xxxv.,  p.    1551.) 
GRASSI,  B.,  and  G.   ROVELLI.     Ric.   embr.   s.  Cestocli.,  Catania,    1892. 


3.     Hymenolepis  lanceolata,  Bloch,   1782. 
Syn.:  Tcenia  lanceolata,  Bloch;  Drepanidotcenia  lanceolata,  Railliet,  1892. 

[This  comes  in  the  genus  Drepanidotcznia. — F.  V.  T.] 
The  parasite  measures  30 — 130  mm.  in  length  and  5 — 18  mm.  in 
breadth  ;  the  head  is  globular  and  very  small ;  the  rostellum  is 
cylindrical,  with  crown  composed  of  eight  hooks  (0*031 — 0*035  mm. 
in  length).  The  neck  is  very  short.  The  short  segments  increase 
gradually  and  equally  in  breadth,  but  only  a  little  in  length  ;  the 
female  glands  lie  on  the  side  opposite  to  that  on  which  the  genital 
pore  is  situated  ;  the  three  elliptical  testes  are  on  the  same  side 
as  the  pores  ;  the  cirrus  is  armed  and  slender.  The  eggs  have 
three  envelopes  and  are  oval  (0-050 — 0*035  mm.),  the  external 
enveippe  is  membranous  and  much  wrinkled,  the  middle  one  is  thick 
and  the  internal  one  very  thin. 

It  inhabits  the  intestine  of  ducks,  geese,  and  diving  birds. 


HYMENOLEPIS   LANCEOLATA 


231 


Zschokke  reports  the  receipt  of  two  specimens  which  a  twelve- 
year-old  boy  in  Breslau  evacuated  spontaneously  at  two  different 
times. 

The  corresponding  cysticercoid,  according 
to  Mrazek,  lives  in  freshwater  cyclops ;  ac- 
cording to  Daday  it  is  likewise  found  in 
Diaptomus  spinosus. 

[The  synonymy  of  this  species  is  as  follows  : 
1727,  Tcenia  anserum,  Frisch  ;  T.  acutissima, 
Pallas  (vide  Krabbe,  1867)  ;  T.  anseris,  Bloch 
(vide  Rud.,  1810) ;  1782,  T.  lanceolata,  Bloch; 
1786,  T.  lanceola,  Batsch  (vide  Rud.,  1810)  ; 
1803,  Halysis  lanceolata  (Bloch,  1782),  Zeder 
(vide  Rud,,  1810)  ;  1858,  Hymenolepis  (Dilepis) 
lanceolata  (Bloch,  1782),  Weinland.  It  occurs 
in  the  following  birds,  Domesticated  ducks 
and  geese,  the  Muscovy  duck  (Cairina  mos- 
chata),  white-headed  duck  (Erismatura  leuco- 
cephala),  the  pochard  (Ay  thy  a  rufina),  and 
the  flamingo  (Ph&nicopterus  antiquorum).  It 
has  been  recorded  from  Great  Britain,  France, 
Denmark,  Austria  and  Germany. — F.  V.  T.] 


FIG.  159. — Hymenolepis 
lanceolata,  natural  size. 
(After  Goeze.)  To  the 
right  above,  two  hooks 
are  illustrated.  120/1. 
(After  Krabbe.) 


LITERATURE. 


BLOCK,    M.    E.       Abhdlg.    v.    d.    Erzg.   d.   Eingeweide- 

Wurmer,  Berlin,  1782. 
FEUEREISEN,   J.     Beitr.  z.   Kenntn.  d.  Taen.     (Z.  f.  w. 

Z.,    1868,  xviii.,  p.    161.) 
WOLFFHUGEL,   K.     Drep.   lane.   Bl.     (C.  f.   B.,   P.   u.  I., 

1900  [i],  xxviii.,  p.  49.) 
ZSCHOKKE,  F.     Hym.  lane.  Bl.  als  Schmar.  d.  Menschen. 

(Ibid.,  1902,  xxxi.,  Orig.,  p.  331.) 
MRAZEK,  A.     Zur  Entw.  einig.  Taenien.     (Sitzgsber.  K.  bohm.  Ges.  d.  Wiss.  Math. 

nat.   Cl.   Prag.,    1896,   Art.   xxxviii.) 
DADAY,   E.   v.     Helm.   Stud.    Einige  in  Siissw.-Entomostr.   leb.   Cercocystis-Formen . 

(Zool.   Jahrb.   Syst.,    1:900,   Part  xiv.) 

Gen.  5.     Davainea,  R.  Blanch,,  1891. 

The  scolex  is  more  or  less  globular  with  a  rostellum  furnished  with  two 
rings  of  hammer-shaped  hooks ;  the  suckers  are  surrounded  by  several 
rings  of  small  booklets  ;  the  genital  pores  are  either  on  the  same  lateral 
border  or  are  irregularly  alternating;  ova,  generally  in  egg  capsules,  are 
usually  present  in  large  numbers,  almost  taking  up  the  whole  of  the  mature 
segments.  This  genus  occurs  chiefly  in  birds. 

[The  larval  stage  of  the  Davaineas  takes  place  in  slugs  (Limax)  and  snails 
(Helix).— F.  V.  T.] 


232 


THE   ANIMAL   PARASITES   OF   MAN 


i.     Davainea  madagascariensis,  Davaine,  1869. 
Syn.  :  Tcenia  madagascariensis  ,  Dav.  ;  Tcenia  demeranensis  ,  Daniels,  1895. 

This  worm  measures  25  —  30  cm.  in  length  ;  the  head  has  four 
large  round  suckers;  the  rostellum  has  90  hooks  (0*018  mm.  in 
length)  :  there  are  500  to  700  segments,  of  which  the  last  hundred  are 
filled  with  eggs  and  form  half  of  the  entire  worm.  The  segments, 
when  mature,  measure  2  mm.  in  length  by  1-4  mm.  in  breadth  ; 
genital  pores  on  the  same  lateral  border  :  about  50  testes  ;  the  uterus 
consists  of  a  number  of  loops,  which  at  each  side  are  rolled  up 
into  ah  almost  spherical  ball  ;  when  filled  with  eggs  the  con- 
volutions unwind,  permeate  the  segment  and  then  lose  their 
wall  ;  the  eggs  lying  free  in  the  parenchyma 
become  finally  surrounded,  one,  or  several  together, 
by  proliferating  parenchymatous  cells  ;  this  is  how 
the  300  to  400  ovarian  vesicles,  taking  up  the 
entire  mature  segment,  are  formed.  The  globular 
oncosphere  (o'OoS  mm.)  is  surrounded  by  two  per- 
fectly transparent  shells  ;  the  external  shell  ter- 
minates in  two  pointed  processes. 

Davainea  madagascariensis  has  hitherto  been 
found  in  man  only.  Davaine  described  this  species 
from  fragments  sent  to  him  from  Mayotte 
(Comores),  and  which  were  found  in  two  Creole 
children,  Chevreau  observed  four  cases  in  Porte- 
Louis  (Island  of  Mauritius),  likewise  in  children  ; 
Leuckart  received  the  first  perfect  specimen  ;  it 
was  obtained  from  a  three-year-old  boy  in  Bang- 

kok'  the  son  of  a  Danish  caPtain  ;  Daniels>  at 

the    post   mortem    of   an    adult    native  of  George 
Town,    Guiana,    found    two     specimens      (Tania 
demerariensis),   and    finally    Blanchard    describes 
another  perfect  specimen  which  was  in  Davaine's 
collection  of  helminths   in   Paris,   and  which  was   obtained  from   a 
little  girl  three   years  old,  of   Nossi-Be    (Madagascar).      The  inter- 
mediary host  is  unknown. 

LITERATURE. 

GRENET  and  DAVAINE.     Not.  sur  une  nouv.  esp.  de  Taenia  rec.  a  Mayotte.     (Mem. 

soc.  biol.,  Paris,  1869  [5]>  i->  P-  233  ',  Arch,  de  med.  nav.,  1870,  xiii.,  p.   134.) 

CHEVREAU,    P.     Le    T.    madagasc.     (Bull.    soc.    med.    de    1'ile    Maurice,    1891,    ix., 

P-   523.) 

BLANCHARD,   P.     Note  sur  quelq.   vers  par.   de  rhomme.     (C.    R.  soc.  biol.,  Paris, 
1891   [9],  iii.,  p.   604.) 


fallen  off. 


DAVAINEA   ASIATICA  233 

LEUCKART,    R.     Ueber    T.    mad.     (Verhandl.    d.    D.    Zool.    Ges.    I.    Leipzig,    1891 

p.    68.) 
DANIELS,    C.    W.     T.    demerariensis.     (Brit.    Guiana   med.    Ann.    Hosp.    Rep.,    1895  ; 

The  Lancet,    1896,   ii.,   p.    1455.) 
BLANCHARD,    R.     Le    Dav.    mad.    a    Guyane.     (Bull.    Ac.    med.,    1897    [3]>    xxxvii., 

P-    34-) 
BLANCHARD,    R.     Un    cas    ined.    de    Dav.    mad.    consid.    sur    le    genre    Davainea. 

(Arch,   parasitol.,    1899,   ii.,    p.    200.) 

2      Davainea  (?)    asiatica  (v.  Linst.)  1901. 
Syn.  :  Tcenia  asiatica,  v.  Linstow. 

There  exists  only  one  headless  specimen  of  this  species, 
which  is  not  quite  adult  and  which  is  preserved  in  the  Zoological 
Museum  of  the  Imperial  Academy  of  Science  in  St.  Petersburg. 
It  came  from  a  human  being  and  was  found  by  Anger  in  Aschabad 
(Asiatic  Russia,  near  the  Northern  frontier  of  Persia).  The  specimen 
measures  298  mm.  in  length.  The  breadth  anteriorly  is  only  0*16  mm., 
the  posterior  part  measures  178  mm.  across.  The  number  of  segments 
is  about  750.  The  genital  pores  lie  on  the  same  lateral  border  ; 
the  testes  are  globular  and  lie  in  a  dorsal  and  ventral  layer  in  the 
medullary  layer  ;  the  cirrus  pouch  is  pyriform,  0-079  mm.  in  length, 
and  0*049  mm.  in  breadth  ;  the  female  glands  lie  in  the  forepart 
of  the  segments,  the  ovary  reaching  to  the  excretory  vessels  ;  the 
vitellarium  is  small  and  round.  The  vagina  has  a  large  fusiform 
receptaculum  seminis  ;  the  uterus  breaks  up  into  60  to  70  large, 
uneven,  ovarian  follicles. 

LITERATURE. 

LINSTOW,    v.     Taenia    asiatica,    eine    neue    Taenie    d.    Mensch.       (C.    f.    B.,    P.    u.    I., 
1901    [i],    xxix.,    p.    982.) 

Gen.   6.     Tcenia,  L.,  1758.  ] 

Taeniidae,  usually  of  considerable  length,  the  mature  segments  of  which 
are  much  longer  than  they  are  broad.  The  scolex  has  a  rostellum  and 


1  The  Greeks  teamed  the  tapeworms  eA/ii»8es  TrAarefoi,  more  rarely 
(=  fascia)  ;  the  Romans  called  them  tcenia,  tinea,  tceniola  ;  later  lumbrici,  usually 
with  the  addition  lati,  to  distinguish  them  from  the  Lumbrici  teretes.  The  pro- 
glottides  were  called  Vermes  cucurbitini  ;  the  cysticerci  x«A«Cai  (hailstones),  later 
hydatids.  Plater  (1602)  was  the  first  to  differentiate  Tcenia  intestinornm  (=  Both- 
riocephalns  latus),  amongst  the  Lumbrici  lati  of  man,  from  Tcenia  longissima  (—  Tcenia 
solium).  The  term  saginata  was  already  used  by  Arnoldus  Villanovanus,  who 
lived  about  1300;  and,  according  to  him,  it  signifies  "  cingulum  "  (belt,  chain); 
while  N.  Andry,  in  1700,  traces  this  word  from  "  solus,"  because  the  worm 
occurs  in  man  alone.  Leuckart  and  Krehl  derive  the  word  "  solium  "  from  the 
Syrian  "  schuschl  "  (the  chain),  which  in  Arabian  has  become  "susl"  or  "  sosl,"  and 
in  Latin  has  become  "  sol-ium."  What  Linne  described  under  the  term  Tcenia 
saginata  was  really  Tcenia  solium  ;  the  latter  was  first  distinguished  by  Goeze,  but 
was  forgotten  until  Kiichenmeister,  in  1852,  again  called  attention  to  the  differences. 


234  THE   ANIMAL   PARASITES   OF   MAN 

usually  a  double  crown  of  hooks,  exceptionally  the  rostellum  is  transformed 
into  an  apical  sucker,  the  primitive  armature  of  which  then  disappears. 
The  neck  may  be  long  or  short.  The  young  segments  are  broader  than 
they  are  long ;  the  fairly  mature  ones  almost  square ;  the  genital  pores 
project  at  the  lateral  borders,  and  alternate  irregularly.  Genitals  single 
in  each  segment. 

The  testes  are  usually  very  numerous,  and  are  situated  in  the  lateral  parts 
of  the  central  field  ;  the  ovary,  shell  gland  and  vitellarium  are  situated  in  the 
posterior  half  of  the  central  field.  The  uterus  has  a  median  trunk  with 
lateral  branches  which  develop  later ;  as  these  develop,  the  testes,  and  later 
on  the  ovary  and  vitellarium,  become  atrophied.  The  egg-shell  is  thin  and  frail, 
round,  and  with  or  without  filaments  ;  the  embryonal  shell  is  thick  with 
radial  stripes.  There  is  a  cysticercus,  ccenurus  or  echinococcus  stage  which 
is  usually  passed  in.  herbivorous  animals  ;  the  adult  stage  is  passed  in  car- 
nivorous animals  and  in  man. 


i.     Tcznia  solium,  L.,  p.  p.,  1767. 

Syn. :  Tania  cucurbitina,  Pall.,  1781 ;  T.  pellucida,  Goeze,  1782  ;  T.  vulgaris, 
Werner,  1782;  T.^lentata,  Gmel.,  1790;  Halysis  solium,  Zeder,  1800;  T. 
humana  armata,  Brera,  1802;  T.  (Cystotcenia]  solium,  Leuck.,  1862,  ;  - 

The  average  length  of  the  entire  tapeworm  is  about  2 — 3  m., 
but  may  be  even  more  ;  the  head  is  globular,  O'6 — 0*8 — ro  mm.  in. 
diameter.  The  rostellum  is  short  with  a  double  wreath  of  hooks, 
22 — 32  in  number,  usually  26 — 28  ;  large  and  small  hooks  alternate 
regularly  ;  the  length  of  the  large  hooks  is  0*16 — 0-18  mm.,  of  the 
small  ones  o-ii — 0*14  mm.  The  rostellum  is  sometimes  pigmented. 
The  suckers  are  hemispherical,  0*4 — 0-5  mm.  in  diameter.  The  neck 
is  fairly  thin  and  long  (5 — 10  mm.).  The  proglottides,  the  num- 
ber of  which  averages  from  800  to  900,  increase  in  size  very 
gradually  ;  at  about  i  m.  behind  the  head  they  are  square  and 
have  the  generative  organs  fully  developed.  Segments  sufficiently 
mature  for  detachment  measure  10 — 12  mm.  in  length  by  5 — 6 
mm.  in  breadth.  The  genital  pores  alternate  fairly  evenly  at 
the  lateral  border  a  little  behind  the  middle  of  each  segment.  The 
fully-developed  uterus  consists  of  a  median  trunk,  with  7 — 10  lateral 
branches  at  either  side,  some  of  which  are  again  ramified.  The  eggs 
are  oval,  the  egg-shell  very  thin  and  delicate ;  the  embryonal  shell 
is  thick,  with  radial  stripes ;  it  is  of  a  pale  yellowish  colour, 
globular,  and  measures  0-031 — 0-036  in  diameter  ;  the  oncospheres, 
with  six  hooks,  are  likewise  globular,  and  measure  0*02  mm.  in 
diameter. 


T^ENIA   SOLIUM 


235 


Malformations  are  not  so  common  as  in  Tcenia  saginatd  ;  they  consist 
of  two  or  several  proglot tides  being  partly  or  entirely  amalgamated,  forma- 
tion of  single  club-shaped  segments,  fenestration  on  long  or  short  series  of 
segments  and  so-called  double  formation,  in  which  the  head  has  six  suckers 
and  the  segments  exhibit  a  Y-shaped  transverse  section.  The  oncospheres 
occasionally  also  possess  more  than  six  hooklets.  Very  slender  specimens 
have  led  to  the  description  of  a  particular  species  or  variety  (T.  tenella). 


FIG.  161. — Two  fairly  mature  pro- 
glottides  of  Tcsnia  solium,  with  sexual 
organs  and  excretory  vessels. 


Head    of    T&nia    solium. 


In  its  fully-developed  condition  Tcenia  solium  is  found  exclu- 
sively in  the  small  intestine  of  man  ;  the  head  is  usually  attached 
in  the  anterior  third,  and  the  chain,  in  numerous  convolutions, 
extends  backwards  ;  a  few  mature  detached  proglottides  usually 
lie  at  the  most  posterior  part,  and  these  are  usually  evacuated 
during  defalcation.  In  exceptional  cases  single  proglottides  or  whole 
worms  may  reach  contiguous  organs  if  abnormal  communications  with 
them  exist,  thus  they  may  reach  the  abdominal  cavity  and  the 
urinary  bladder,  or  they  may  be  found  in  a  s?-called  worm  abscess 
of  the  peritoneum  ;  occasionally,  in  vomiting,  single  segments  or 
several  together  may  be  brought  up. 

The  cyslicercus  stage  (Cysticercus  cellulosce,  fig.  136)  that  gives 
rise  to  Tcenia  solium  lives  normally  in  the  intramuscular  connective 
tissue  and  other  organs  of  the  domestic  pig,  but  it  is  known  to 
exist  also  in  a  few  other  mammals,  such  as  the  wild  boar,  the 


236 


THE   ANIMAL   PARASITES   OF   MAN 


sheep,1  the  stag,  dog,  cat,  brown  bear  and  monkey,  as  well  as 
in  man.  The  cysticercus  of  the  pig  is  an  elliptical  vesicle  with  a 
longitudinal  diameter  of  6 — 20  mm.,  and  a  transverse  diameter  of 
5 — TO  mm. 

Even  with  the  naked  eye.  a  white  spot  may  be  observed  in  the 
centre  of  the  long  equator,  this  being  the  invaginated  head  ;  it  is 
easy  to  make  it  project  by  pressing  on  the  vesicle,  and  on  examin- 
ing it  under  the  microscope  one  can  convince  oneself  that  it 
corresponds  with  the  head  of  Tcenia  solium. 


FIG.   163. — Large  and  small  hooks  of  Tcenia  solium,  280/1. 
(After  Leuckart). 


a  b 

FIG.    165. —  Two 

FIG.  164. — (a]  Ovum  of  Tcsnia  solium  yiith  fully-developed  mature  proglottides 
embryo  ;  the  residue  of  the  vitellus  within  the  egg-shell.  of  T,  solium  with 
(b)  Isolated  embryo  of  T.  solium  within  the  embryonal  shell.  fully  developed 
450/1.  uterus.  2/1. 

Numerous  experiments  have  proved  that  the  Cysticercus  cellu- 
lose of  the  pig,  if  introduced  into  the  intestine  of  man,  grows  to  a 
Tcenia  solium  (Kuchenmeister  1855,  Humbert  1856,  Leuckart  1856, 
Hollenbach  1859,  Heller  1876)  ;  the  cysticercus  has  frequently  also 
been  cultivated  purposely  by  feeding  pigs  with  mature  proglot- 
tides of  Tcenia  solium.  (P.  J.  van  Beneden  1853,  Haubner  and 
Kiichenmeister  185  5  ^Leuckart  1856,  Hosier  1865,  Gerlach  1870, 
&c.)  ;  but  success  did  not  attend  the  efforts  to  make  Cysticercus 
cellulosce  settle  in  the  intestine  of  pigs,  dogs,  guinea-pigs,  rabbits 

1  The  cysticerci,  which  on  rare  occasions  are  found  in  the  muscular  system  of 
sheep,  are  either  strayed  specimens  of  Cysticercus  tenuicollis,  which  normally  develop  in 
organs  of  the  abdominal  cavity,  and  appertain  to  Tcenia  marginata  of  the  dog,  or 
Cysticercus  cellulosce.  (Compare  "Bongert,  in  Zeitschr.  /.  Fleisch  u.  Milchliyg.,  1899,  ix., 
p.  86.) 


T^NIA    SOLIUM 


237 


and  monkeys  (Macacus  cynomolgus),  and  thus  transform  them  into 
taenise ;  the  attempts,  also,  to'  infect  dogs  with  cysticerci  were 
likewise,  as  a  rule,  abortive.1 

The  development  of  Cysticercus  celluloses  takes  two  and  a  half  to 
three  or  four  months  ;  it  is  not  known  how  long  the  cysticerci  remain 
alive  in  animals  ;  not  uncommonly  they  perish  at  earlier  or  later  stages, 
and  become  calcined  or  caseated.  Extracted  cysticerci  die  in  water  at  a 
temperature  of  47-48°  C.,  in  flesh  at  normal  temperature  they  remain  alive 
for  twenty-nine  days  or  more.  On  account  of  the  present  rapid  means  of 
pickling  and  smoking  meat  the  cysticerci  as  a  rule  are  not  killed,  but  the 
effect  of  cold  on  them  for  some  time  is  certain  death  (Ostertag). 

There  is  not  the  least  doubt  that  human  beings  are  almost 
exclusively  infected  with  Tcenia  solium  by  eating  pork  containing 
cysticerci,  in  a  condition  that  does  not  endanger  the  life  of  the 
cysticerci.  The  infection  may  likewise  be  caused  in  man  by  eating 
the  infected  meat  of  other  animals  subject  to  this  species  of  bladder 
worm,  though  practically  this  means  of  infection  only  occurs  excep- 
tionally in  consequence  of  the  rarity  of  Cysticercus  cellulose  in  the 
stag,  sheep  and  dog. 

Pigs,  on  the  other  hand,  are  much  more  liable  to  be  affected  with 
cysticerci,  but  the  conditions  have  considerably  improved  since  the  intro- 
duction of  official  inspection  of  cattle  and  meat  ;  in  the  Kingdom  of  Prussia 
there  was  on  an  average  one  infected  pig  to  every  305  slaughtered  between 
1876-1882  ;  from  1886-89,  there  was  i  to  551  ;  from  1890-92,  there  was 
i  to  817  ;  in  1896,  i  to  1,470,  and  in  1899,  i  to  2,102  ;  in  the  kingdom 
of  Saxony  in  1894  there  was  i  infected  pig  to  every  636;  in  1895  there 
was  i  to  every  2,049,  and  m  1896  only  i  infected  pig  was  found  of  5,886 
slaughtered.  In  South  Germany  pigs  with  cysticerci  are  very  rare,  but  are 
more  frequent  in  the  eastern  provinces  of  Prussia  ;  in  1892  the  number  of 
infected  pigs  compared  to  the  total  slaughtered  were  as  follows  : — 

In  the  district  of  Marienwerder    . .          . .          . .  i  :      28, 


Oppeln  ..  ..i 

„              „          Konigsberg  .  .      i 

„              „          Stralsund  and  Posen  . .          .  .          . .  i 

„  -            ,,          Danzig,  Frankfort  a.  O.  and  Bromberg  . .      i 

as  compared  with  the  district  of  Arnsberg          .  .          .  .  i 

Coblenz  ..      i 

„                  „                „         Diisseldorf       .  .          .  .  .  .      i 

Miinster  and  Wiesbaden  i 


80, 
108, 
187, 
250, 
865, 

975, 
1,070, 
1,900. 


The  average  for  the  whole  of  Prussia  in  the  same  year  was  1:1,290,  for 
the  eastern  provinces  on  the  other  hand,  i  :  604.  The  cause  for  this  is 
most  likely  attributable  to  the  manner  in  which  the  pigs  are  kept.  When 

1  According  to  Gerlach  only  young  pigs  (up  to  six  months  old)  are  capable  ot 
infection,  and  perhaps  the  failures  may  have  been  due  to  the  anima.ls  chosen 
for  experiment  being  of  the  wrong  age. 


238  THE    ANIMAL    PARASITES    OF    MAN 

allowed  to  be  in  the  farmyards  of  the  small  farmers  for  the  whole  day  or 
allowed  to  wander  in  the  village  streets  and  pasture  lands,  they  are  more 
liable  to  take  up  the  oncospheres  of  the  Tcenia  solium  than  when  shut  up 
in  good  pigstyes. 

The  geographical  distribution  of  Tcenia  solium  generally 
corresponds  with  that  of  the  domestic  pig  and  the  custom  of 
eating  pork  in  any  form  insufficiently  cooked  or  raw.  There 
are  or  were  some  isolated  districts  in  Germany,  France,  Italy  and 
England  where  the  "  Armed  tapeworm  "  was  frequent  (for  instance, 
Thuringia,  Brunswick,  Saxony,  Hesse,  Westphalia,  whereas  it  is  and 
was  very  scarce  in  South  Germany)  ;  it  is  thus  easily  understood 
why  it  occurs  very  rarely  in  the  East,  in  Asia  and  in  Africa,  in  con- 
sequence of  the  Mahommedans,  Jews,  &c.,  not  eating  pork.  In 
North  America,  also,  Tcenia  solium  is  very  rare  ;  the  tapeworm 
which  is  known  there  by  this  name  is  generally  Tcenia  saginata 
(Stiles).  During  the  last  decades  tapeworm  infection  has,  however,  con- 
siderably decreased  in  North  and  East  Germany  in  consequence  of  the 
precautions  exercised  by  the  public  in  the  'choice  of  pork  to  avoid 
trichinosis,  especially,  however,  because  meat  infected  with  cysti- 
cercus  must  be  sold  for  what  it  is  and  must  be  thoroughly  cooked 
before  being  placed  on  the  market ;  indeed,  if  badly  infected  it 
may  not  be  sold  for  food,  but  can  be  turned  to  account  for  industrial 
purposes. 

The  occurrence  of  Cysticercus  cellulosce  in  man  has  been  known 
since  1558  (Rumler,  Obs.  med.,  liii.,  p.  32) ;  there  is  hardly  an 
organ  in  man  in  which  cysticerci  have  not  been  observed  at 
some  time  ;  they  are  most  frequently  found  in  the  brain,1  where 
they  grow  to  a  variety  known  as  Cysticercus  racemosus  ;  next 
in  frequency  they  are  found  in  the  eye,  in  the  muscular  system, 
in  the  heart,  in  the  subcutaneous  connective  tissue,  the  liver, 
lungs,  abdominal  cavity,  &c.  The  number  of  cysticerci  observed 
in  one  man  varies  between  a  few  and  several  thousands.  Of 
the  sexes,  men  are  most  subject  (60  to  66  per  cent,  of  the  number 
attacked).  The  disturbances  caused  in  man  by  cysticerci  vary 
according  to  the  nature  or  position  of  the  organs  attacked  ;  when 
situated  in  the  cerebral  meninges  they  have  the  same  effect  as 
tumours. 

1  Dressel,  for  instance,  examined  87  persons  suffering  from  Cysticercus,  and 
found  it  seventy-two  times  in  the  brain,  thirteen  times  in  the  muscles ;  K. 
Miiller,  in  36  cases,  found  it  twenty-one  times  in  the  brain,  twelve  times  in  the 
muscles,  three  times  in  the  heart  ;  Haugg  in  25  cases,  found  it  thirteen  times  in 
the  brain,  six  times  in  the  muscles,  twice  in  the  skin,  &c.  According  to  Graefe, 
amongst  1,000  ophthalmic  cases  in  Halle  and  Berlin,  there  was  one  with  cysti- 
cercus  in  the  eye ;  in  Stuttgart  there  was  only  one  in  4,000 ;  in  Paris  one  in 
6,000,  and  in  Copenhagen  one  in  8,000. 


T^NIA    SOLIUM  239 

During  the  last  decades,  however,  these  cases  have  also  become 
less  common  ;  thus,  according  to  Virchow,  since  the  introduction 
of  official  inspection  of  meat,  the  number  of  cases  of  cysticercus 
of  the  brain  has  fallen  from  i  in  every  31  post  mor terns  to  i  in 
every  280  ;  Hirschberg  between  1869  and  1885  discovered  cysticerci 
in  the  eye  seventy  times  in  60,000  ophthalmic  cases,  but  during 
the  following  six  years  the  parasite  was  only  present  twice  amongst 
a  total  of  46,000  cases  of  ophthalmic  diseases. 

The  infection  of  human  beings  with  cysticerci  can  only  take 
place  by  the  introduction  of  the  oncospheres  of  Tcenia  solium  into 
the  stomach  with  vegetable  foods,  salads  that  have  been  washed 
in  impure  water  containing  oncospheres,  also  by  drinking  con- 
taminated water ;  the  carriers  of  Tcenia  solium,  moreover,  infect 
themselves  still  more  frequently  through  uncleanliness  in  defaeca- 
tion,  the  privies  in  public  localities  and  many  private  houses 
contributing  to  this  cause.  The  minute  oncospheres  can  thus 
easily  reach  the  fingers  and  thence  the  mouth  (as  in  twirling 
the  moustache,  biting  the  nails).  More  rarely  a  third  manner  of 
transmission  or  internal  auto-infection  may  possibly  take  place, 
as,  when  in  the  act  of  vomiting,  mature  proglottides  near  the 
stomach  are  drawn  into  it  ;  the  oncospheres  or  segments  there 
retained  are  then  in  the  same  position  as  if  they  had  been  intro- 
duced through  the  mouth. 

On  account  of  these  dangers  of  internal  or  external  auto-infection,  it 
is  therefore  the  duty  of  the  medical  attendant,  after  recognising  the  presence 
of  tapeworms,  to  expel  them/  and  in  doing  so  to  employ  every  possible  means 
to  prevent  vomiting  setting  in  ;  it  is,  however,  equally  important  to  take 
the  necessary  steps  to  destroy  the  parasites  evacuated.  It  may  be  inci- 
dentally mentioned  that  in  using  certain  remedies  the  scolex  not  rarely  remains 
in  the  intestine  ;  the  cure  in  such  cases  has  not  been  accomplished,  as  the 
scolex  again  produces  new  proglottides,  and  after  about  eleven  weeks  the 
xfirst  formed  ones  are  again  mature  and  appear  in  the  faeces. 

Amongst  the  Cysticerci  also  many  malformations  appear  ;  thus  absence 
of  the  rostellum  and  the  hooks  ;  or  double  formation  with  six  suckers,  or 
abnormalities  of  growth  on  account  of  the  surroundings,  and  which  have 
had  a  particular  name  given  to  them  :  Cysticercus  racemosus,  Zenk. 
(  =  C.  botryoides,  Hell.;  C.  multilocularis ,  Kuchenm.)  ;  these  forms  are  more 


1  The  diagnosis  as  a  rule  is  not  difficult  ;  the  patients  themselves  frequently 
observe  the  pumpkin-seed-like  segments  in  the  faeces.  But  in  such  cases  the  diagnosis 
must  still  be  confirmed.  In  other  cases  the  discovery  of  tne  oncospheres  in  their 
shells,  which  cannot  be  confounded  with  the  other  constituents  of  the  faeces,  gives 
complete  certainty,  although  the  differential  diagnosis  between  T.  solium  and  T. 
saginata  is  hardly  possible  from  the  oncospheres  ;  but,  if  evacuated  segments  are  placed 
between  two  slides  and  lightly  pressed,  the  species  is  easily  recognisable  by  the  shape 
of  the  utuers. 


240  THE   ANIMAL   PARASITES   OF   MAN 

especially    found    at    the    base    of     the    brain,    are    irregularly    ramified    and 
often  without  the  head. 

A  certain  interest  is  attached  to  those  forms  that  have  led   to 
the  establishment  of  a  distinct  species  : 


Cysticercus  acanthotrias,  Weinl.,  1858. 

In  making  the  autopsy  of  a  white  Virginian  woman  who  had  died  of 
phthisis,  a  Cysticercus  was  found  on  the  dura  mater,  and  eleven  or  twelve 
specimens  in  the  muscles  and  subcutaneous  tissue.  Weinland1  and  Leuckart/ 
who  examined  the  specimens,  found  that  they  resembled  Cysticercus  cellu- 
loses in  form  and  size,  but  that  they  carried  on  the  rostellum  a  triple  crown, 
each  consisting  of  14  to  1 6  hooks,  which  differed  from  the  hooks  of  Cysticercus 
celluloses  or  of  T&nia  solium  by  the  greater  length  of  the  posterior  root 
process  and  the  more  slender  form  of  the  hooks  ;  the  large  hooks  measured 
0-153 — 0-196  mm.,  the  medium-sized  hooks,  0*114 — 0-14,  and  the  small  ones 
0*063 — 0-07. 

On  account  of  these  differences  a  distinct  species  of  Cysticercus 
was  established,  and  this  naturally  presupposed  a  corresponding 
species  of  Tsenia  (T.  acanthotrias,  Lkt.) ;  this  could  be  done  with 
justice  as  long  as  the  case  remained  isolated,  i.e.,  in  America,  as 
there  was  the  possibility  of  the  resulting  taenia  being  found.  In  this 
respect,  however,  the  position  has  changed  ;  Delore3  first  described 
a  Cysticercus  the  size  of  a  nut  from  the  biceps  muscle  of  the 
arm  of  a  silk-worker  in  Lyons  ;  according  to  Bertolis  this  speci- 
men possessed  hooks  of  three  different  sizes,  the  dimensions  of 
which  corresponded  with  the  figures  given  by  Weinland  and 
Leuckart ;  the  correctness  of  the  diagnosis  could  hardly  be  doubted, 
as  Bertolis  was  known  to  be  a  very  conscientious  observer.  A 
second  case  has  become  known  through  Cobbold4  who  regards  a 
specimen  of  a  Cysticercus  in  Dallinger's  collection,  as  likewise 
belonging  to  Cysticercus  acanthotrias  ;  this  specimen  also  came 
from  a  man's  brain  ;  finally  a  third  case,  also  from  France,  has 

1  Weinland,  D.  F.,  "  An  Essay  of  the  Tape- worms  of  Man,  illus.  with  orig.  woodc.,' 
Cambridge,  U.  S.,  1858  ;   "  System.  Catalog,  aller  Helminthen,  die  im  Menschen  gefunden 
werden  "  (Arch.  /.  Naturgesch.,  1859,  25.     Jhrg.,  i.,  p.  276  ;   "  Be.schreibung  zweier  neuer 
Taenioiden  aus  dem  Menschen"  &c.  (Nov.  Act.  Acad,  Leop.-Caes,   1861,  xxviii.,  with 
5    plates. 

2  Leuckart,  R.,    Die^mensch.    Paras,    u.    d.    v.    ihnen    herrurh.    Krankh.,    1863,    i., 
p.   310. 

3  Delore,    X.,    "  Cysticercus    acanthotrias    observe    chez    une   jeune   fille  "    (Mem.    et 
Compt.  rend.  soc.  sc.   med.,  Lyon,   1863,  vol.  ii.,  p.   202). 

4  Cobbold,  T.  Sp.,   "  On  a  rare  and  remarkable  Parasite  from  the  collection  of  the 
Rev.  W,  Dallinger  (Rep.  Fortieth  Meet.  Brit.  Assoc.  Adv.  Scienc.,  1870-71,  not.,  p.  135). 


CYSTICERCUS   ACANTHOTRIAS  241 

been  published  by  Redon.1  This  author,  amongst  numerous 
Cysticerci  cellulosce  of  a  man,  found  one  that  had  41  hooks  in  three 
rows,  and  he  was  the  first  to  express  the  opinion  that  Cysticercus 
acanthotrias  does  not  represent  a  distinct  species,  but  is  only  an 
abnormality  of  Cysticercus  cellulosce.  This  view  was  also  taken  by 
Blanchard  and  Railliet,  and  is  probably  correct,  as  the  discovery 
of  the  large  Tcenia  belonging  to  it  and  furnished  with  three  rows 
of  hooks  is  not  to  be  expected  in  European  beasts  of  prey,  and  in 
Redon's  case  Cysticercus  acanthotrias  as  well  as  Cysticercus  cellulosce 
occurred  simultaneously. 

The  duration  of  life  of  Cysticercus  cellulosce  in  man  is  very 
long  ;  cysticerci  of  the  eye  have  been  known  to  persist  for 
twenty  years,  and  in  Cysticercus  of  the  brain  ten  to  nineteen 
years  may  elapse  from  the  first  appearance  of  cerebral  symptoms 
until  death.  Dead  cysticerci  may  shrivel  up  or  become  calcified, 
perhaps  also  become  fatty-degenerated  and  then  absorbed.  Finally, 
it  may  be  mentioned  that  if  particular  proof  is  required  that  Cysti- 
cercus cellulosce  of  man  is  connected  with  the  cycle  of  development 
of  the  Tcenia  solium,  such  proof  has  been  furnished  by  Redon  (I.e.). 

NOTE.  —  Tcenia  tenella,  mentioned  on  p.  214,  was  ascribed  by  Cobbold 
to  Cysticerci  of  the  muscular  system  of  sheep.  It  has,  however,  been 
demonstrated  that  these  cysticerci  belong  to  the  cycle  of  development  of 
Tcenia  marginata  (dog)  (Cyst,  tenuicollis,  from  the  omentum  of  sheep)  ; 
but,  as  already  stated,  Cysticercus  cellulosce  also  occurs  in  sheep.  Chatin 
himself  swallowed  the  cysticercus,  which  Cobbold  termed  Cysticercus  ovis, 
without  causing  a  taenia  to  develop  in  his  intestine.  Miiller  also  vainly 
sought  to  induce  the  colonisation  of  Cysticercus  tenuicollis  in  his  own 
person.  On  the  other  hand,  the  feeding  of  a  dog  with  Cysticercus  ovi-. 
resulted  in  the  production  of  Tcenia  marginata. 

LITERATURE. 

The  most  important  literature  on  Tcenia  solium  and  Tcenia  saginata  :  — 

KUCHENMEISTER,  E.     Ueb.   Cest.  i.  Allg.  u.  die  d.  Mensch.    insbes.    Zittau,    1853.  — 

Exper.  Nachw.,  dass  Cyst,  cellul.  sich  in  Taenia  solium  umwandelt.     (Wien.  med. 

Wchschr.  1855,  1856,  No.  i,  p.  319.  —  Dtsche.  Klinik.,  1860,  xii.,  p.  187), 
LEUCKART,  R.     Die  Blasenbandw.  u.  ihre  Entw.,  Giessen,  1856. 

Finnenzust.   d.  T.   medioc.     (Gott.   Nachr.,    1862,  pp.    13  and   195). 

Thier.,  Paras,   d.   Mensch,    ist  and   2nd  edit. 
HAUBNER.      In   Mag.    f.  d.  ges.  ,  Thierhlkde,    1854,     xx.,    pp.     243     and     366;     1855, 

xxi.,  p.  100. 

GERLACH,    A.    C.      Fiitterungsvers.   bei  Schweinen    mit    T.     solium.     (Jhrsber.      Kgl. 
Thierarzneisch.,    Hannover,    1869   [l87o].   "•.   PP-   66  anci  69-) 


1  Redon,  "  Exp.  sur  le  dev.  rubanaire  de  Cyst,  de  I'homme  "  (C.  R.  Ac.  sc. 
Paris,  1877,  vol.  Ixxxv.,  p.  675;  Gaz.  mtd.  Paris,  486  ann.,  1877,  p.  510;  Arch. 
v&ttv.  publ.  d  Vtcole  d'Alfort,  1877,  ii.,  p.  910;  Ann.  d.  sc.  nat.  Zool.,  1877  [6], 
vi.,  art.  No.  4.) 

16 


242  THE   ANIMAL   PARASITES    OF    MAN 

MOSLER,   F.     Helm.    Stud.   u.   Beob.,   Berlin,    1864. 

SOMMER,   F.     Bau  u.   Entw.   d.   Geschlechtsorg.  v.   T.   medioc.   u.   T.   solium.     (Z.  f. 

w.   Zool.,    1874,   xxiv.,   p.   499.) 
LEWIN.     Cyst.    cell.    u.    sein   York.    i.    d.    Haut    d.    Mensch.     (Charite-Annal.,    1877, 

ii.,   p.    609;    Arch.    f.    Dermat:,    1894,    xxvi.,   pp.    71    and    217.) 
PERRONCITO,   E.     Esp.    s.    prod,    del    Cyst,    della    T.    medic.     .     .     (Ann     R.    Ace. 

agric.,  Torino,    1877,   xx  ;   Zeitschr.   f.  Vet.-Wiss.,    1877,  v.) 
STEUDENER,  F.     Unters.  iib.   d.  Bau  d.  Cest.     Halle,    1877. 
MONIEZ,   R.     Ess.   monogr.   sur  les  Cyst.     (Trav.   inst.   zool.   Lille.,    1880   [i],   iii.); 

Mem.    sur   les   Cest.     (Ibid.,    1881    [2],    iii.) 
ZENKER,  F.  A.     Cyst,  racem.   d.   Gehirns.     Bonn.,    1882. 

BENEDEN,  E.  v.  Rech.  s.  le  dev.  embr.  de  quelqn.  Ten.  (Arch,  de  biol.,  1881,  ii.,  p.  183.) 
BERENGER-FERAND,  L.  J.  B.  Le9_  clin.  sur  les  Tenias  de  1'homme.  Paris,  1888. 
SCHWARZ.  Zur  Unterscheidung  der  Cyst.  cell.  v.  C.  tenuicollis.  (Zeitschr.  fur 

Fleisch-   und   Milchhyg.,    1893,   iii.,   p.    89.) 

2.  Tcenia  marginata,  Batsch,  1786. 
Syn.  :    T.   e.   Cysticerco   tenuicolli,   Kuchenmeister,    1853. 

This  species,    which  in    structure  ^resembles    Tesnia    solium,    lives    in  the 
intestine   of   the   dog   and    the  wolf.      It    attains    1-5 — 4    m.    in    length,    pos- 
sesses   a    double    crown    of    thirty    to    forty    hooks  ;    on    an    average    thirty- 
six    to    thirty  -  eight     hooks, 
and    in    its   cysticercus   stage 
(Cysticercus    tenuicollis}    lives 
in  monkeys,  pigs,  sheep  and 
oxen. 

It  is  included  in  this  work 
because,     according     to     one 
statement,    Cysticercus    tenui- 
collis   is     supposed    to    have 
Fir,  i66.-Large  and     small    booklets  of  Tvnia      ^Qn    observed    in     man'     in 
marginal*.     280/1.     (After  Leuckait.)  North     America-        B»t      the 

case  is    not  quite  certain,  as 
the     number    of    hooks    was 

less  than  in  Cysticercus  tenuicollis,  and  coincided  with  Cysticercus  cellulose  • 
although  the  size  of  the  cysticercus]!  appeared  to  point  to  Cysticercus 
tenuicollis.  A  yet  earlier  statement  of  Eschricht,  that  C.  tenuicollis  had  been 
observed  in  Iceland  in  the  liver  of  a  man,  is  undoubtedly  due  to  an  error. 


3.  Tcenia  serrata,  Goeze,  1782. 

This  parasite  attains  a  length  of  from  0-5—2  m.,  possesses  a  double 
crown  of  thirty-four  to  forty-eight  (mostly  forty)  hooks.  It  lives  exclusively 
in  the  intestine  of  the  dog,  the  corresponding  cysticercus  (Cysticercus  pisi- 
formis}  living  in  the  abdomen  of  the  hare  and  rabbit.  We  mention  this 
species  with  all  reserve  amongst  the  parasites  of  man,  because  Vital-  states 

1  Braun,  M.,  "  Helm.  Notizen  II L  Cyst,  tenuicollis  und  C.  acanthotrias  beim 
Menschen  "  (C.  /.  B.  u.  P.,  1894,  xv.,  p.  409). 

*  Vital,  A.,  "  Les  entozoaires  d,  I'hoptial  de  Constantine  "  (Gaz.  med.  Paris,  1874,  p. 
285). 


TJENIA  :    CKASSICOLLIS,   SAGINATA  243 

that  he  has  observed  it  twice  in  Constantine  (Algeria)  in  human  beings.  The 
descriptions,  however,  are  not  sufficiently  explanatory  to  characterise  the  species. 
It  is  highly  probable  that  they  relate  to  Tcenia  solium.  Galli  Valerio  even 
swallowed  five  specimens  of  Cysticercus  pisiformis,  but  without  result.1 

4.     Tcenia  crassicollis,  Rud.,  1810. 

I  only  mention  this  species  from  the  intestine  of  the  domestic  cat  because 
Krabbe  regards  its  occurrence  in  man  as  possible.  It  attains  a  length  of 
60  cm.  and  is  armed  ;  its  cysticercus  (Cysticercus  fasciolaris}  lives  in  the 
liver  of  mice  and  rats.  In  Jutland,  according  to  Krabbe,  chopped-up 
mice  (spread  upon  bread)  are  eaten  raw,  being  a  national  remedy  for 
retention  of  urine,  and  this  custom  affords  the  possibility  of  the  intro- 
duction of  Cysticercus  fasciolaris  into  the  intestine  of  man  (Nord.  med. 
Arkiv.,  1880,  xii.). 

5.    Tcenia  saginata,  Goeze,  1782. 

Syn.  :  T.  solium,  L.,  1767  (pro  parte)  ;  T.  cucurbitina,  Pallas,  1781  (p.p.)  ; 
T.  inermis,  Brera,  1802;  Moquin-Tandon,  1860;  T.  dentata,  Nicolai,  1830; 
T.  lata,  Pruner,  1847  ;  Bothriocephalus  tropicus,  Schmidtmuller,  1847  j 
T.  mediocanellata ,  Kiichenmeister,  1855  ;  T.  zittavensis,  Kchmst.,  1855  ; 
T.  tropica,  Moquin-Tandon,  1860  ;  T.  (Cystotcenia)  mediocanellata,  Leuckart, 
1863. 

The  length  of  the  entire  tapeworm  averages  4 — 8 — 10  m.  and 
more,  even  up  to  36  m.  According  to  Berenger-Feraud  it  attains 
a  length  of  74  m.  (?)  The  head  is  cubical  in  shape,  1-5 — 2  mm. 
in  diameter  ;  the  suckers  are  hemispherical  (o-8  mm.),  and  are 
frequently  pigmented  ;  there  is  a  sucker-like  organ  in  place  of  the 
rostellum,  and  this  also  is  frequently  pigmented.  The  neck  is 
moderately  long  and  about  half  the  breadth  of  the  head ;  the 
proglottides,  the  number  of  which  averages  more  than  1,000, 
gradually  increase  in  size ;  the  mature  detached  segments  are  shaped 
exactly  like  pumpkin-seeds,  and  are  about  16 — 20  mm.  in  length 
and  4 — 7  mm.  in  breadth.  The  genital  pores  alternate  irregularly 
and  are  situated  somewhat  behind  the  middle  of  the  lateral  border. 
There  are  twenty  to  thirty-five  lateral  branches  at  each  side  of 
the  median  trunk  of  the  uterus,  and  these  again  ramify.  The  eggs 
are  more  or  less  globular,  the  egg-shell  frequently  remains  intact 
and  carries  one  or  two  filaments  ;  the  embryonal  shell  is  thick, 
radially  striated,  is  transparent  and  oval ;  it  is  0-3 — 0*04  mm.  in 
length,  and  0-02 — 0-03  mm.  in  breadth.  Several  segments  simul- 
taneously are  usually  passed  without  defaecation. 


Galli- Valerio,   C.  /.   B.,   P.   u.   I.,"  1898   [i],   xxiii.,   p.   941. 


244 


THE    ANIMAL    PARASITES    OF    MAN 


Malformations  are  not  uncommon,  and  resemble  those  of  Tcenia  solium  ; 
a  triangular  form  has  been  termed  T.  capensis  by  Kiichenmeister,'  and 
T.  lophosoma  by  Cobbold,  names  that  naturally  possess  as  little  value  as  does 
the  term  T.  fenestrata  for  fenestrated  specimens.  Moreover,  T.  solium,  var. 
abietina,  Weinl.,  1858,  which  was  evacuated  by  an  Indian,  was  probably 
a  T.  saginata,  with  somewhat  close  uterine  branches. 


Tcenia  saginata  in  its  adult  condition  lives  exclusively  in  the 
intestinal  canal  of  man.1  The  corresponding  cysticercus  is  called 
Cysticercus  bovis,  and  is  found  almost  exclusively  in  the  ox  ;  it- 
is  small,  7-5—9  mm-  in  length,  and  5-5  mm.  in  breadth,  may 
easily  escape  notice  and  requires  from  three  to  six  months  for  its 

development.  Numerous  experi- 
ments have  confirmed  the  con- 
nection of  Cysticercus  bovis  with 
Tcenia  saginata  ;  indeed,  the 
cysticercus  was  only  discovered 
by  feeding  experiments  after 
attention  had  been  called  to  the 
ox  as  the  probable  intermediary 
host  of  this  Tcenia. 


FIG.  167.  —  Ma- 
ture segment  of 
Tcenia  saginata,  G., 
with  distended 
uterus.  2/1. 


FIG.  _i68.— Ceph- 
alic end  of  Tcenia 
saginata  in  the  con- 
tracted cpndition. 


Medical  men  observed  that  weakly 
children,  who  were  ordered  to  eat 
raw  scraped  beef  to  strengthen  them, 
contracted  Tcenia  saginata.  It  was 
found,  moreover,  that  Jews,  -who  are 
prohibited  from  eating  pork  from 
religious  motives,  suffered  especially 
from  T.  saginata  ;  when  T.  solium 
was  found  to  occur  in  a  Jew  he  often 
confessed  to  having  eaten  pork  ;  and 

finally  it    was    found    that  certain  nations — for    instance,   the    Abyssinians— 
frequently  harbour  T.  saginata,  and  only  eat  beef — raw  by  preference. 

These  observations  led  Leuckart  in  1861  to  feed  young  calves  with  the  pro- 
glottides  of  T.  saginata  in  order  to  discover  the  corresponding  cysticercus, 
which  was  then  not  known.  This  experiment  was  successful.  Similar  experi- 
ments, with  similar  results,  were  then  conducted  by  Mosler  (1863),  Cobbold 
and  Simonds  (1864  and  1872),  Roll  (1865),  Gerlach  (1870),  Ziirn  (1872), 
Saint  Cyr,  Jolicosur  (1873),  Masse  and  Pourquier  (1876),  and  Perroncito, 
in  1876.  The  attempts  to  infect  goats,  sheep,  dogs,  pigs,  rabbits  and 
monkeys  were  unsuccessful.  Only  Zenker  and  Heller  were  able  to  infect  kids, 
and  Heller  infected  one  sheep,  but  these  are  exceptions. 


.'  Abnormal  migrations  of  this  species  have  also  been  known.  Compare,  amongst 
others,  Stieda,  A.,  ''  Ditrchbohr.  d.  Duod.  11.  d.  Pancreas  ditrck  einc  Taenia  " 
(C.  /.  B.,  P.  u..I.,  1900,  xxviii,  [i],  p.  430). 


T.3ENIA    S  AGIN  AT  A 


245 


Artificial  infections  of  human  beings  with  Cysticercus  bovis 
to  obtain  the  tapeworm  were  less  nume- 
rous and  indeed  quite  superfluous,  yet 
this  was  also  done  by  Oliver  (1869)  in 
India,  and  Perroncito  (1877)  in  Italy.  The 
experiments  of  the  latter  prove  that  the 
extracted  cysticerci  of  the  ox  certainly  perish 
in  water  at  47 — 48°  C. 


It  is  a  remarkable  circumstance  that,  at  least 
as  regards  Central  Europe,  Cysticercus  bovis  in  the 
ox,  after  natural  infection,  was  so  seldom  found, 
that  almost  every  case  was  published  as  a  rarity ; 
whereas  the  taenia  is  very  frequent  in  man.  The 
reason  for  this  is,  that  in  Germany  cattle  are 
not  severely  infected,  and  that  the  small,  easily- 
dried-up  cysticerci  easily  escape  notice  in  the  large 
body  of  the  host.  Hertwig,  the  late  director  of 
the  town  cattle  market  in  Berlin,  in  1888,  pointed 
out  that  the  cysticercus  of  the  bx  is  found  chiefly 
in  the  musculi  pteryogoidei  externi  and  interni, 
and  since  that  time  a  far  greater  number  of 
infected  oxen  have  been  found  in  Berlin. 

Since  1892  an  increase  has  taken  place  in  the 
number  of  oxen  infected  with  cysticercus,  but  this 
is  probably  attributable  to  the  more  general 


FIG.   169. — A  piece  of 
the  muscle  of  the  ox,  with 
three  specimens  of  Cysti- 
cercus bovis,  natural  size. 
(After  Ostertag.) 


Year 

Number  of  Oxen 

Infected 

Proportion 

-  Slaughtered 

1888—89 

141,814 

H3 

:  1,125 

1889—90 

154,218 

390 

:     395 

1890  —  91 

124,593 

263 

:     474 

1891  —  92 

136,368 

252 

:      541 

.1892—93 

142,874 

214 

:     672 

and  searching  examinations.     In  the  slaughter-houses  of  Prussia  the  number 
of  infected  beasts  was  as  follows  : — 


1892 


1894 

1895 
1896 
1897 


567 
686 
748 

i,i43 
1,918 
2,629 


The  condition  was  most  frequent  in  Neisse  (3-2 — 4  per  cent.),  Eisenach  (i'9i 
per  cent.),  Ohlau  (1*57  per  cent.),  Oels  i.  Schles  (i  per  cent.),  Marienwerder 
(0-34—1-2  per  cent.).  The  flesh  of  oxen  only  slightly  infected  (containing  not 
more  than  ten  living  cysticerci)  is  sold  in  pieces  of  not  more  than  5  Ibs.  to 


246 


THE    ANIMAL    PARASITES    OF    MAN 


consumers  after  having  been  rendered  innocuous  by  cooking,  or  by  pickling  for 
twenty-one  days  in  25  per  cent,  salt  brine,  or  hanging  for  twenty-one  days  in 
suitable  refrigerators  ;  oxen  in  which  only  one  cysticercus  is  found  are 
allowed  free  commerce,  and  those  strongly  infected  (i.e.,  containing  more 
than  ten  living  cysticerci)  may  only  be  used  for  industrial  purposes. 

The  cysticercus  of  the  ox  has  hitherto  been  found  in  man  on 
very  rare  occasions.  Arndt  (Zeitschr.  f.  Psych.,  xxiv.)  mentions  a 
case  in  the  brain,  Heller  in  the  eye,  and  Nabiers  and  Dubreith 
also  in  the  brain.  (Journ.  mcd.  Bordeaux,  1889-90,  p.  209)  ;  but 
the  diagnoses  are  not  quite  certain,  as  absence  of  hooks  also 
occasionally  occurs  in  Cysticercus  celluloses. 

Tcznia  saginata  is  the  most  frequent  tapeworm  of  man  (with 
the  exception  of  Dibothriocephalus  latus  in  a  few  districts),  and  the 
parasite  is  widely  distributed  over  the  surface  of  the  globe  ;  it  has 
been  known  in  the  east  for  ages ;  according  to  accounts  received, 
it  is  frequent  in  Africa,  America  and  Europe.  Its  frequency  has 
perceptibly  increased  during  the  last  few  years,  but  a  decrease 
should  soon  take  place  in  consequence  of  the  extent  and  improve- 
ment of  the  official  inspection  of  meat. 

The  following  table  shows  the  relative  frequency  of  the  ces- 
todes  of  man  : — 


Author 

v-    :  Nrirf    T.'^-. 

T.  so- 
lium 

Dibr. 
latus 

1 

Dipyl        Un- 
canin.   decided 

| 

Parona  (Milan)    .  .           .  .           1899 

I5O                          121 

ii        4 

14 

Parona  (Italy) 

1868  —  99 

513                   397 

71  !  26 

19 

Krabbe  (Denmark) 

1869 

IOO 

•37 

53  i     9 

I 

>»                » 

!  869—  86 

200 

153 

24      16 

8        — 

»                » 

1887—95 

IOO 

89 

— 

5 

6        — 

Blanchard  (Paris) 

? 

IOOO 

21        

—  <     — 

Stiles  (United  States)     .  . 

1895 

more    than 

more    than 



3 

—        — 

300 

300 

Schoch  (Switzerland)     .  . 

1869 

19 

1.6 

I 

2 

—        — 

Zaeslein  (Switzerland)   .  . 

1881 

?                    1  80 

19 

?        

Kessler  (St.  Petersburg) 

1888 

? 

22 

16 

47 

—        — 

Mosler  (Greifswald) 

1894 

181 

112 

64 

5 

—  '     

Bellinger  (Munich) 

1885 

25 

16            i 

8 

—        — 

6.     Tcenia  africana,  v.  Lstw.,  1900. 

This  worm  measures  over  1-3  m.  in  length.  The  segments 
are  all  broader  than  they  are  long.  The-  scolex  is  unarmed  and 
is  provided  with  an  apical  sucker  (0*16  mm.).  The  parasite  measures 
1-38  mm.  in  breadth,  1-03  mm.  in  width ;  the  suckers  measure 
0*63  mm.  in  diameter.  The  neck  is  verv  short  and  somewhat 


AFRICANA 


247 


broader  than  the  scolex  ;  number  of  segments  about  600  ;  the  hind- 
most segments  measure  7  mm.  in  length  and  12 — 15  mm.  in  breadth. 
The  genital  pores  alternate  irregularly  in  the  middle  of  the  border 


FIG.  170. — Nearly  mature  segment  of  Tcenia  africana,  magnified.  (After  v. 
Linstow.)  The  ovary  is  in  the  middle,  and  behind  it  are  the  shell-gland  and 
vitellogene  gland;  at  the  sides  are  the  testicular  vesicles,  and  the  excretory  canals 
pass  to  the  exterior  ;  the  cirrus  pouch,  the  vas  deferens  and  the  vagina  are 
on  the  left. 


FIG.     171. — Proglottis    of    Tcenia    africana,    with    uterus,    magnified.     (After    v. 
Linstow.) 

of  the  segments  ;  the  testes  are  very  numerous  and  occupy  the 
entire  medullary  layer  ;  the  vas  deferens  is  much  convoluted  ;  the 

cirrus  pouch  is  pyriform  and  thick 
walled ;  the  cirrus  and  vagina  are  beset 
with  bristles  directed  outwards  ;  the  re- 
K-j  I  ^  ^"JB  ceptaculum  seminis  is  fusiform  ;  the 
ovary  is  large  and  double,  and  consists  of 
radially  placed  club-shaped  tubes  that  do 
not  anastomose  and  do  not  branch ;  the 
vitellogene  gland  is  at  the  posterior  border 
of  the  proglot tides,  the  round  shell- 
gland  in  front  of  it ;  the  uterus  consists 
FIG.  172.  — Head  of  Tcenia  of  a  median  trunk  and  fifteen  to  twenty- 

afncana  ;   apical  surface  ;     mag-      ..  . 

nified.     (After  v.  Linstow.)          four    non-rammed    lateral    branches    on 

each  side  ;  the  embryonal  shell  is  thick 

and  has  radial  stripes — it  may  be  round  (0-0312 — 0-0338  mm.)  or 
oval  (0-0390 — 0*0338  mm.)  ;  the  booklets  of  the  oncospheres  measure 
•0078  mm.  in  length  (fig.  131,  a). 


248 


THE   ANIMAL   PARASITES   OF   MAN 


At  present  only  two  specimens  are  known  ;  they  came  from  a 
black  soldier  from  the  vicinity  of  Lake  Nyassa.  The  cysticercus 
is  unknown  ;  perhaps  it  lives  in  the  zebu,  the  flesh  of  which  the 
Askaris  are  in  the  habit  of  devouring  uncooked.1 

7.     Tcenia  confusa,  Ward,  1896. 

Length  8\5  m.,  breadth  about  5  mm.  The  scolex  is  unknown  ; 
there  is  no  neck ;  number  of  proglottides  700  to  800,  always  longer 
than  they  are  broad  ;  the  hindmost  measure  35  mm.  in  length,  4 — 5 
mm.  in  breadth  ;  the  genital  pores  alternate  irregularly  behind 


FIG.    173.  —  Tcema    confusa  ;    fairly 
mature  segment.     15/1.     (After  Guy er.) 


FIG.  174.  —  Tania 
confusa.  Mature  seg- 
ment. 25/1.  (After 
Ward.) 


the  middle  of  the  lateral  border ;  testicular  vesicles  numerous  ; 
vas  deferens  not  much  coiled ;  the  cirrus  pouch  thick-walled, 
elongated  and  club-shaped,  with  globular  vesicula  seminalis ;  the 
cirrus  is  beset  with  little  hairs  ;  the  receptaculum  seminis 
is  globular ;  ovary  small,  double  ;  each  half  is  bean-shaped  ; 


1  v.  Linstow,  "  Tania  africana,  eine  neue  Tcenia  d.  Menschen  aus  Afrika 
(C.  f.  B.,  P.  u.  I.,  '1900  [i],  xxviii.,  p.  485);  "Helm.  v.  Ufer  d.  Nyassasees 
(Jen.  Zeitschr.  /.  Naturw.,  1900,  xxxv.,  p.  420). 


TJEXIA    ECHINOCOCCUS  249 

vitellogene  gland  narrow,  triangular  ;  shell-gland  globular  ;  uterus 
with  median  trunk  and  fourteen  to  eighteen  short  ramified  lateral 
branches  on  either  side.  The  oncospheres,  which  have  shells,  are 
oval  (0*039 — °'3°  mm.)  ;  the  shell  is  thick  and  radially  striated. 

Of  this  species  only  two  specimens  have  been  recorded  ;  they 
occurred  in  human  beings  and  were  sent  at  different  times  to  the 
first  describer  of  them  by  a  doctor  in  Lincoln  (Nebr.).  Perhaps 
Tcenia  solium,  var.  abietina,  Weinld.,  which  was  found  in  a  Chipe- 
way  Indian,  is  of  the  same  species  in  spite  of  the  shorter 

segments. 

• 

LITERATURE. 

WARD,    H.   B.     Rep.    of    the    Zoologist.     (Ann.    rep.    Nebraska    State    Board    Agric. 

f.,    1895-6,   p.    257  ;   ibid.,    f.    1896-7,   p.    173.) 
A    New    Hum.   Tape-worm.     (West.    Med.    Rev.,    1896,    i.,    p.    35  ;    Proc.    Nebr. 

State  Med.   f.,    1896,   p.    83.) 

Note  on  T.   confusa.     (Zoolog.   Anzeiger,    1897,   xx->   P-    321-) 

GUYER,    M.    F.     On    the    Struct,    of    T.    confusa.     (Zoolog.    Jahrb.,    Part    f.  Syst., 
1898,    xi.) 


8.     Tcenia  echinococcus,  v.  Sieb.>  1853. 

Syn.  :    Tcenia   nana,    v.    Ben.,    1861    (nee.  v.   Sieb.,    1853). — Echinococcifer 
echinococciis ,  Weinl.,  1861. 

Tcenia  echinococcus  measures  2*5  to  5  or  6  mm.  in  length  ;  the 
head  is  0*3  mm.  in  breadth,  and  has  a  double  row  of  twenty- 
eight  to  fifty  booklets  on  the  rostellum. 

The  size  and  form  of  these  booklets  vary  (the  larger  ones  are 
0*040 — 0*045  mm.  in  length,  the  smaller  ones  are  0*030 — 0*038 
mm.  in  length).  The  suckers  measure  0*13  mm.  in  diameter  ;  the 
neck  is  short  ;  there  are  only  three  or  four  segments,  the  posterior 
segment  being  about  2  mm.  in  length  and  0*6  mm.  in  breadth. 
The  genital  pores  alternate  ;  there  are  forty  to  fifty  testicular 
vesicles  ;  the  vas  deferens  is  spirally  coiled  ;  the  cirrus  -pouch 
is  pyriform.  The  ovary  is  horseshoe-shaped  with  the  concavity 
directed  backwards  ;  the  vitellogene  gland  double,  each  half  almost 
bean-shaped,  at  right  angles  to  the  level  of  the  segment  ;  the 
shell-gland  is  round.  The  median  trunk  of  the  uterus  is  dilated 
when  filled  with  eggs  and  (instead  of  lateral  branches)  has  lateral 
protuberances.  It  is  not  unusual  for  the  eggs  to  form  local  heaps. 
The  embryonal  shell  is  moderately  thin,  with  radiating  fibres, 
almost  globular,  0*030 — 0*036  mm.  in  diameter. 

When  mature  this   parasite  lives  in   the  small  intestine  of  the 


250 


THE   ANIMAL    PARASITES    OF    MAX 


domestic  dog,   the  jackal,   and  the  wolf,   and  is  usually  present  in 
great  numbers.1      The  cysticercus  stage  (Echinococcus  polymorphus) 

lives    in    various    organs  —  chiefly    in    the 
liver  and  lungs  —  of  numerous   species    of 
mammals  (twenty-seven),  especially  in  the 
sheep,  ox  and  pig,  and  it  is  even  not  un- 
common  in   man,   though   the  tsenia  itself 
has  never  been  found  in  a  human  being  ; 
accordingly  man  can  only  acquire  the  Echi- 
nococcus  by   ingesting   the   oncospheres  of 
the    "  dog   worm."     The  dogs  disseminate 
the  oncospheres  of  T.  echinococcus  wherever 
they  go,   or   carry   them    to  their    mouths 
and    coats    by    biting    up    the    evacuated 
segments,  and   are    thus   able   to   transmit 
them  directly  to  human  beings  (by  licking 
them   or  making  use  of  the  same  crockery, 
&c.).      In     other     cases    the    oncospheres, 
which  are  enclosed  in   a  shell,  must  with- 
stand   desiccation    for    a  time    and    then 
(as    when     the     dogs    are     "  kissed "     or 
otherwise    caressed)     are   transmitted   into 
or  on   to   man.      As   echinococcus    disease 
'  in     man    is    always     very    dangerous,     it 
would  be   a   matter  of  general  interest  to 
prevent  dogs  being  infected  by  destroying 
the   echinococci,2  and   all   measures   would 
be    justifiable   which    would   diminish   the 
superfluous     number     of    house-dogs     (for 
instance,     high    taxes)  ;    measures    should 
also  be   adopted   to  limit    the   association 

coccus.  50/1.  The  cirrus  pouch,  of  men  with  dogs,  particularly  in  such 
shee,l-gfa^  aT^eiS  frequented  places  as  restaurants,  railway 
gland,  and  the  testicuiar  vesi-  carriages  and  tramcars. 

cles  at  the  sides  are  recognis- 
able in  the  second  proglottis ; 
the  posterior  proglottis  shows 
the  uterus  partly  filled  with 

eggs,    as    well    as    the  cirrus  '  In  Iceland  28  per  cent,  of   the  dogs  are   infected 

pouch   and   the  vagina.  with  this  taenia,    in  Lyons  j-\   per  cent.,  in  Zurich  3-9 

per   cent.,    in   Berlin  i  per  cent.,  and  in  Copenhagen 

0-4  per  cent.  In  Australia  even  40-50  per  cent,  of  the  dogs  are  affected.  It  is,  how- 
ever, a  question  whether,  in  addition  to  T.  echinococcus,  a  second  analogous  form  is 
not  involved  ;  as  the  form  from  Canis  dingo  attains  a  length  of  10 — 30  mm. 

-  Mosler,     F.,     "  Ueb.     Mittel     z.     Bekdmpfg.     endem.    vork.     Echinococcuskrankh." 
(Dlsche.   Medic.-Ztg.,    1889,   No.   72). 


FIG.    175.  —  Tcsnia    echino- 


T^ENIA    ECHINOCOCCUS 


251 


Echinococcus  is  very  common  in  slaughtered  animals  ;  in  Germany,  how- 
ever, the  figures  in  the  reports  of  the  abattoirs  present  an  erroneous 
view  in  so  far  as,  besides  the  total  number  of  animals  slaughtered,  only 
the  numbers  of  those  organs  (liver  and  lungs)  are  published  that  were  so 
severely  infected  with  echinococci  that,  even  when  the  parasites  were  cut 
out,  the  flesh  could  not  be  placed  upon  the  market  and  was  therefore 
"  condemned." 


FIG.    176. — Section    through    an    Echinococcus   cyst    with    brood    capsules.      (From 
a  wax  model.) 

In    Berlin    the   following   animals   were    slaughtered  :— 


Year 

1888-89 

1889-90 

1890-91 

1891-92 

1892-93 

1896-97 

Oxen 

Sheep 
Pigs 

141,814    I 
338,798 

154,218 
430,362 
442,115 

124,593 
371.943 

472,859 

136,368 

367,933    j 
530,551 

142,874 
355,949    i 
518,073    i 

146,612 

395,769 
694,170 

During  the  same  years   the  following  were  condemned  in  consequence  of 
being   infected   with   Echinococci  :— 


Lung 

Liver 

Lung        Liver 

Lung 

Liver 

Lung 

Liver 

Lung 

Liver 

Lung 

Liver 

Oxen    .  . 
Sheep   v 
Pigs      .  . 

6,578 
5,041 
5,910 

2,668 

3,363 

5,285 

7,266  :  2,418 

5,479    2,742 
6,523  ;  5,078 

5.792 

4.595 

5,083 

L938 
2,059 

3.735 

4,497 
4,435 
6,037 

1,721 
1,669 

4,374 

2,563 
3,331 
6,785 

739 
1,161 
4,312 

3,284 
4,56l 
7,888 

1,156 

!,939 
5,398 

Nevertheless   there   are   statistics   that   give   the   total  number  of  animals 
infected  with  Echinococcus  : — 


Author 

Place 

Oxen                              Sheep 

Pigs 

Langrich 

.  .      Rostock  i.  M. 

26'2  % 

37-o  % 

5'4  % 

Olt 

.  .   j  Stettin 

7'i  % 

25-8  % 

7'3  % 

S  tending 

.  .   j  Gothn 

24-6  % 

35'4  % 

21-4  % 

Prettner 

.  .   j  Prague 

23-2  % 

C'C    o/ 

5  5   /o 

? 

In  Giistrow,  in  Mecklenburg,  half  of  the  animals  slaughtered  are  said  to 
be  infected  with  Echinococcus  ;  in  Wismar  25  per  cent,  of  the  oxen, 
15  per  cent,  of  the  sheep  and  5  per  cent,  of  the  pigs  are  infected  ;  accord- 
ing to  Mayer,  in  Leipzig,  3-79  per  cent,  native  pigs,  24-47  per  cent.  Hun- 


252 


THE    ANIMAL    PARASITES    OF    MAN 


garian  pigs,  and  i3'O9  per  cent,  of  sheep  were  infected  with  Echinococcus  ; 
at  the  same  time  it  was  stated  .that  in  regard  to  the  native  pigs  the  liver 
was  more  frequently  affected  than  the  lungs  (3-81  per  cent,  as  compared 
with  0-26  percent.);  in  sheep  the  lungs  were  more  frequently  infected  (12-71 
per  cent,  to  3-73  per  cent.),  whereas  in  the  Hungarian  pigs  both  organs 
were  almost  equally  infected  (14-78  per  cent,  to  12-03  Per  cent.). 


STRUCTURE  AND  DEVELOPMENT  OF  ECHINOCOCCUS 
(CASEWORM). 

Echinococcus  is  represented  by  a  spherical  or  roundish  bladder 
full  of  a  watery  liquid  which  originates  from  the  oncosphere,  and 
in  man  may  attain  the  size  of  a  child's  head,  but  remains  smaller 


f*  FIG.  177. — Echinococcus  veterinorum,  natural  size.  The  fibrous  sac  enclosing 
the  Echinococcus  has  been  opened  and  laid  back  in  five  parts,  so  that  the  sur- 
face of  the  bladder-worm  may  be  seen  with  the  brood  capsules  showing  through 
it.  (After  Leuckart.) 

in  cattle  (the  size  of  an  orange  or  apple).  The  thin  wall  of  the 
bladder  is  composed  of  an  external  stratified  cuticle,  and  an  internal 
germinal  or  parenchymatous  layer  (endocyst).  The  latter  again 
exhibits  two  layers  ;  an  outer  layer  of  small  cells  that  are 
not  very  distinct,  and  an  inner  layer  of  larger  cells.  It  con- 


r\ 


STRUCTURE    AND    DEVELOPMENT    OF    ECHINOCOCCUS  253 

tains,  in  addition,  calcareous  corpuscles,  muscular  fibres  and  excretory 
vessels. 

The  development  in  cattle  often  remains  stationary  at  this 
stage,  and  they  are  then  called  "  acephalocysts "  or  echinococcus 
cysticus  sterilis.  In  other  cases  large  numbers  of  small,  hollow  "  brood 
capsules  "  are  formed  within  the  internal  space,  but  are  not  arranged 
in  any  particular  order.  The  order  of  the  layers  is  just  the  reverse 
in  them  to  what  it  is  in  the  parent  cyst,  that  is  to  say,  they  are 
clad  inside  by  a  thin  cuticle  and  carry  the  parenchymatous  layer 
on  their  external  surface.  Scolices  (fig.  176)  form,  internallv  or 


FIG.  178. — A  piece  of  the  wall  of  an  Echinococcus  veterinorum  stretched  out 
and  seen  from  the  internal  surface.  50/1.  A  few  brood  capsules  with  scolices  directed 
towards  the  interior  and  exterior. 

externally,  their  number  being  variable  (three  to  twenty  or  even 
more).1  This  form  occurs  chiefly  in  domesticated  animals  and  is 
termed  Echinococcus  veterinorum,  Rnd.,  or  Echinococcus  cysticus 
fcrtilis. 

In  man,  and  only  rarely  in  cattle,  the  mother  cyst  first  forms 
''  daughter  cysts  "  (Echinococcus  hominis,  Rud.,  fig.  179),  which, 
though  smaller  than  the  "  mother  cyst,"  resemble  it  in  the  struc- 
ture of  their  walls  ;  thus  they  are  covered  externally  by  a  stratified 

'  Goldschmidt,  R.,  "  Z.  Entw.  d.  Echinococcuskopfchen  "  (Zool.  Jahrb.  Anat., 
1900,  part  xiii.,  p.  467). 


254  THE   ANIMAL    PARASITES    OF    MAN 

cuticle  and  internally  by  the  parenchymatous  layer.  They 
originate  between  the  strata  of  the  cuticle  of  the  mother  cyst 
from  small,  detached  portions  of  its  parenchymatous  layer  ;  during 
their  growth  they  bulge  inwardly  or  outwardly  and  may  separate 
themselves  entirely  from  their  parent  cyst.  '  In  the  latter  case 
they  lie  between  the  mother  cyst  and  the  capsule  of  con- 
nective tissue  formed  by  the  host  (Ech.  granulosus  or  Ech. 
hydatidosus  exogenus)  ;  when  growing  inwardly  they  reach  the 
interior  of  the  mother  cyst  (Ech.  hydatidosus  endogenus).  Their 
number  is  very  variable  and  does  not  depend  on  the  size  of  the 
mother  cyst. 


FIG.  179. — Echinococcus  hominis  in  the  liver,  reduced.  The  fibrous  capsule 
and  the  wall  of  the  echinococcus  have  been  incised,  so  that  the  daughter  cysts  may 
be  seen.  (After  Ostertag,  from  Thoma.) 

The  endogenous  "  daughter  cysts "  are  attributed  by  some 
authors  to  transformed  brood  capsules  and  to  scolices  that  have 
fallen  off  the  mother  cyst.  However  feasible  this  theory  sounds, 
there  can  be  no  doubt  that  the  views  of  the  less  recent  observers 
are  correct.  Sterile  mother  cysts,  however,  also  occasionally  con- 
tain daughter  cysts,  and  these  Naunyn  considers  to  arise  from 
parts  of  the  wall  of  the  mother  cyst,  constricted  off. 

The  "  daughter  cysts "  may  be  constituted  like  the  "  mother 
cysts."  that  is  to  say,  they  may  remain  sterile,  or  may  produce 
brood  capsules,  or  again  other  cysts,  which  are  called  "  grand- 
daughter cysts."  The  mother  cyst  may  perish,  so  that  the  cysts 
then  lie  in  the  internal  space  of  the  connective  tissue  capsule. 


STRUCTURE   AND    DEVELOPMENT  OF    ECH1NOCOCCUS 


255 


The  echinococcus  fluid,  which  originally  is  formed  from  the  blood  of 
the  host,  is  light  yellow,  with  a  neutral  or  slightly  acid  reaction  ;  its 
specific  gravity  averages  10,09  to  10,15.  It  contains  about  1-5  per  cent, 
of  inorganic  salts,  half  of  which  is  common  salt  ;  in  addition  (besides  water) 
it  contains  sugar,  inosite,  leucine,  tyrosin,  succinic  acid  (associated  with 
lime  or  soda)  and  albumens  which  are  not  coagulated  by  warmth  ;  occa- 
sionally also  the  fluid  has  been  found  to  contain  haematoidine  and  uric  acid 
salts  (in  echinococcus  of  the  kidneys),  which  doubtless  demonstrates  that  the 
echinococcus  liquid  originates  from  the  host  ;  finally,  there  is  present  a 
substance  with  toxic  properties  (leucomaine)  which,  if  introduced  into  the 
abdominal  cavity,  causes  peritonitis,  which,  as  a  rule,  has  a  fatal  termination.1 

According  to  the  researches  of  Leuckart,  the  growth  of  the 
echinococcus  is  very  slow  ;  four  weeks  after  infection  the 
average  size  is  only  0-25 — 035  mm.,  at  the  age  of  eight  weeks  it 
is  i — 2'5  mm.,  and  at  this  period  the  formation  of  the  central 
cavity  commences ;  at  the  age  of  five  months  and  with  a  size 
of  15 — 20  mm.  the  first  brood  capsules  with  scolices  are  formed. 
The  consequence  of  this  gradual  increase  of  size  is  that  the 
organ  attacked  can  maintain  its  functions  by  vicarious  hypertrophy, 
and  that  many  echinococci  induce  no  special  symptoms  and  cannot 
even  be  diagnosed,  the  latter  circumstance  being  due  to  their  hidden 
position. 

The  Echinococcus  cannot  be  said  to  be  scarce  in  man,  as  is 
shown  by  the  following  table  for  Central  Europe  :— 


Place                                                   Period 

No.  of 
Sections 

No.  of  cases 
of  Ech. 

Percentage 

Rostock          ..           ..           ..           .  .         1861  —  83 

I,O26 

25 

2'43 

Greifswald     .  .           .  .           .  .           .  .    •      1862  —  93 

3,429 

51 

I-48 

Tena   .  .          .  .          .  .          .  .          '.  .    I     1866  —  87 

4,998 

42 

0-84 

Breslau           1866—76 

5,128 

39 

0761 

Berlin              1859—68 

4,770 

33 

0*69 

Wiirzburg 

2,280 

ii 

0-48 

Gottingen 

639 

3 

0-469 

Dresden          ..           ..           ..           ..    i      1852  —  62 

i,939 

7 

0-36 

Munich           1854—87 

14,183 

35 

0-25 

Vienna            .  .           .  .           .  .           .  .             1860 

1,229 

3 

0-24 

Prague 

1,287 

3 

0-23 

Kiel                ..          1872—87 

3,58i 

7 

0-19 

Zurich,  Basle,  Berne 

7,982 

II 

0-13 

Erlangen        .  .           .  .           .  .           .  .         1862  —  73 

i,755 

2 

O'l  I 

These,  however,  are  only  cases  that  have  become  known  by 
post  mortem  ;  in  addition  there  are  cases  that  have  been  treated 
medically,  of  which  there  are  a  few  statements,  at  all  events 

1  Drago,    U.,   Ric.   sull'    azione   di   ale.    lig.    idatid.   e   significato    biol.    dci   mcdesmi 
Rassegna   internaz.   d.   Med.   mod.,    1900,   i.,   No.    16,   and  other  authors. 


256  THE   ANIMAL   PARASITES    OF    MAN 

relating  to  the  principal  districts  of  Germany.  According  to 
Madelung,  one  case  of  echinococcus  occurs  to  every  1,056  inhabi- 
tants in  the  town  of  Rostock,  in  the  district  of  Rostock  one  to 
every  1,283,  in  Schwerin  one  to  every  5,887,  and  in  Ludwigsort 
one  to  every  23,685  ;  according  to  Peiper  (in  Up:er  Pomerania), 
one  case  occurs  to  every  3,336,  in  the  district  of  Greifswald  one 
to  every  1,535  inhabitants.  The  northern  districts  of  Pomerania 
are  more  affected  than  the  southern  ones. 

Accordingly,  Echinococcus  is  also  considerably  more  frequent  in  cattle. 
On  an  average  in  Germany  10*39  per  cent,  oxen,  9*83  per  cent,  sheep, 
and  6'47  per  cent,  pigs  are  infected,  whereas  in  Upper  Pomerania 
37-73  per  cent,  oxen,  27-1  per  cent,  sheep  and  12*8  per  cent,  pigs  are 
infected;  in  Griefswald,  indeed,  64-58  per  cent,  oxen,  51-02  per  cent, 
sheep,  but  only  4-93  per  cent,  pigs  are  infected  ;  in  accordance  with 
these  figures  Tania  echinococcus  must  be  frequent  in  dogs  in  Pomerania, 
especially  in  Upper  Pomerania  ;  on  the  other  hand,  the  conjecture  that 
the  frequency  of  Echinococcus  in  Mecklenburg  is  explained  by  the  occurrence 
of  Tcenia  echinococcus  in  foxes  has  not  been  confirmed. 

Beyond  the  European  Continent,  Echinococcus  is  frequent  in 
the  inhabitants  of  Iceland  as  well  as  in  those  of  Australia.  In 
Iceland,  according  to  Finsen,  one  person  is  affected  with  Echino- 
coccus to  every  forty-three  inhabitants  ;  according  to  Jonassen  the 
proportion  is  i  :  63  ;  this  is  due  either  to  the  habits  of  the  people  of 
Iceland  or  to  the  frequency  of  Tcenia  echinococcus  in  dogs,  and  the 
prevalence  of  the  "  bladder-worm  "  in  cattle.  In  certain  districts 
of  Australia  it  is  just  as  frequent.  In  Cape  Colony,  Egypt  and 
Algeria  Echinococcus  is  not  rare,  but  it  is  scarce  in  America  and 
in  Asia,  with  the  exception  of  the  Nomadic  tribes  by  Lake 
Baikal. 

Echinococcus  attacks  persons  of  every  age,  though  it  is  rare 
in  children  up  to  ten  years  of  age  and  in  old  people.  It  occurs 
most  frequently  between  the  ages  of  21  and  40  years.  According 
to  all  statistics  it  preponderates  in  women  (about  two-thirds  of 
the  cases).  The  liver  is  its  favourite  seat  (50  to  69  per  cent,  of 
the  cases)  ;  next,  in  order  come  the  kidneys,  lungs,  cranial  cavity, 
genitalia,  organs  of  circulation,  spleen,  &c.  As  a  rule  one  organ 
only  is  invaded  ;  multiple  occurrence  may  originate  from  one  in- 
fection, or  eventually  from  a  later  infection,  or  it  may  come  to 
pass  that  from  some  cause  (through  the  spontaneous  rupture  of 
an  echinococcus,  or  the  rupture  of  one  caused  by  an  injury  or 
surgical  operation)  daughter  cysts,  brood  capsules  or  scolices  escape 


ECHINOCOCCUS    MULTILOCULARIS 


257 


into    the    abdominal    cavity,1    where  they    may  colonise  or   become 

transformed   and   go  on    growing.      This    possibility,    suggested    by 

clinical  observations,  was  first  experimentally  confirmed  by  Lebedeff 

and  Andrejew  by  the  transplantation  of  echinococcus  cysts  of  man 

into     the     abdominal    cavity     of 

rabbits  ;    though   all    the    subse- 

quent     experimenters      in      this 

direction  did  not  obtain  positive 

results  yet  there  are  a  sufficient 

number  of  successes  (Stadnitzky, 

Alexinsky,  Riemann). 

The  echinococci  may  die  off  at 
various  stages  of  development,  be- 
come caseous  or  calcined,  or  may  be 
absorbed,  the  cause  for  this  being 
either  disease  of  the  bladder-worm  it- 
self or  inflammation  of  its  connective- 
tissue  capsule  ;  the  discovery  of  the 
stratified  cuticle,  which  has  great 
powers  of  resistance,  or  the  finding  of 
the  booklets  of  the  scolices  are  suffi- 
cient to  form  a  conclusion  as  to  the 
nature  of  such  formations. 


wac; 

was 


first 

nrst 


FIG.  180.  —  Hooklets  of  Echinococcus. 
600/1.  (a)  Of  Echinococcus  veterinorum  ; 
^  of  T(snia  echinococcus,  three  weeks 

after  infection  .  (c}  of  the  aduU  r.  echi. 

to     rear     Tcenia      echinoCOCCHS     in      nococcus  ;   (d)  the  three  forms  of   hooklets 

the   dog    by  feeding   it  with   the     S^t.^  within  * 
Echinococci  of  cattle  and  especially 

of  sheep.  Kiichenmeister,  van  Beneden,  Leuckart,  Railliet  and  others 
obtained  similar  results,  and  Thomas,  Naunyn,  Krabbe  and  Finsen 
succeeded  in  rearing  T.  echinococcus  in  dogs  from  the  bladder- 
worms  of  human  beings  ;  these  grow  comparatively  slowly  (one  to 
three  months)  and  only  develop  their  hooklets  in  their  definitive  form 
(fig.  180).  Finally,  Leuckart  infected  young  pigs  by  feeding  them 
with  mature  segments. 

Echinococcus  multilocularis  (Alveolary  colloids). 

In  addition  to  the  form  of  echinococcus  already  described  and 
which  is  also  frequently  termed  Echinococcus  unilocularis,  there  is 
a  second  form  which  occurs  in  man  as  well  as  in  animals  and  which 


1  In  such  cases  the  toxic  effects  of  the  echinococcus  fluid  usually— if  not 
always — manifest  themselves.  Such  effects  are  manifested  by  severe  symptoms  of 
poisoning  being  set  up,  by  urticaria,  peritonitis,  and  ascitis,  and  not  infrequently 
they  cause  a  fatal  termination. 


258  THE   ANIMAL    PARASITES    OF    MAN 

is      termed     Echinococcus     multilocularis,     s.     alveolaris     (alveolary 
colloid.) 

It  was  originally  regarded  as  a  mere  proliferation,  and  its  animal 
nature  was  first  established  by  Zeller  and  R.  Virchow.  The  para- 
site, which  varies  in  size  from  that  of  a  fist  to  a  child's  head, 
presents  a  collection  of  numerous  cysts,  measuring  between  0*1  and 
3 — 4 — 5  mm.  in  diameter,  which  are  embedded  in  a  connective  tissue 
stroma  ;  the  cut  surface  has,  therefore,  a  honeycomb  appearance. 
The  cysts  are  surrounded  by  a  pellucid  and  stratified  cuticle,  and 
each  according  to  its  size  encloses  either  solid  cellular  contents  or 
a  space  cavity  lined  by  a  parenchymatous  layer  ;  the  fluid  contained 
in  such  a  cavity  may  be  transparent  or  is  rendered  opaque  by 
globules  of  fat,  gall  pigment,  haematoidine  and  fat  crystals.  Accord- 
ing to  a  few  authors  all  or  most  of  these  cysts  intercommunicate  ; 
others  state  that  this  is  the  case  at  least  as  regards  the  cuticle. 


FIG.  181. — Echinococcus  multilocularis  in  the  liver  of  the  ox;  natural  size.  (After 
Ostertag.) 

The  scolices  are  by  no  means  found  in  all  the  cysts,  and  when 
present  in  only  a  few,  rarely  half  of  the  cysts  contain  scolices  (one 
or  several)  ;  it  is  supposed  that  at  least  some  of  these  little  heads 
are  formed  in  brood  capsules. 

One  circumstance  is  peculiar  to  the  multilocular  echinococcus 
of  man,  namely,  the  disintegration  that  sets  in  at  certain  stages  ; 
in  the  centre  of  the  parasite  a  cavity  forms  that  frequently  becomes 
very  large  and  is  filled  with  a  purulent,  or  brownish  or  brownish- 
green  viscid  fluid  ;  within  this  fluid  one  finds  shreds  of  the  wall 
of  the  cavity,  calcareous  bodies,  echinococcus  cysts,  also  scolices 
and  booklets,  as  well  as  fat  globules  and  crystals  of  haematoidine, 
margarine  and  cholesterine  and.  concretions  of  lime.  Such  ulcera- 


ECHINOCOCCUS    MULTILOCULARIS  259 

tive  processes,  according  to  Ostertag,  are  never  present  in  the 
multilocular  echinococcus  of  oxen,1  in  which  the  separate  cysts  are 
larger  and  the  connective  tissue  integument  less  powerfully  developed. 
Hardly  anything  positive  is  known  with  regard  to  the  develop- 
ment of  the  alveolar  echinococcus  ;  its  peculiar  conformation  is 
attributed  by  some  to  enormous  agglomerations  of  oncospheres,  by 
others  to  the  abnormal  situation  of  one  oncosphere  ;  a  few 
authors  ascribe  it  to  agglomerations  in  lymphatic  vessels,  others 
to  agglomerations  in  the  biliary  ducts  or  to  peculiarities  of  the 
surrounding  hepatic  tissue  ;  Leuckart  ascribes  it  to  a  grape-like 
variety  of  form  which  continues  budding  ;  a  few  more  recent 
authors  consider  multilocular  echinococcus  to  be  specifically  different 
from  unilocular  echinococcus,  and  therefore  also  different  the 
species  of  tsenia  arising  from  them.  Melnikow-Raswedenkow  is  also 
of  this  opinion.  According  to  this  author  the  oncospheres  settle 
in  the  lumen  of  a  branch  of  the  portal  vein  in  Glisson's  capsule 
of  the  liver  and  grow  into  an  irregularly-shaped  formation  (chitinous 
convolution),  which  breaks  through  the  vascular*  walls  and  thus 
forms  the  alveola.  So  far  the  views  coincide  well  with  Leuckart's 
opinion  of  the  original  grape-like  form  of  the  Echinococcus  nmlti- 
locularis  ;  according  to  Melnikow-Raswedenkow  the  "  granular 
protoplasmatic  substance "  (parenchymatous  layer)  is  not  only 
present  in  the  interior  of  the  loculi  but  also  outside,  and,  moreover, 
"  ovoid  embryos  "  are  supposed  to  develop  in  the  chitinous  con- 
volutions, which,  "  thanks  to  their  amoeboid  movements,  reach  the 
lumen  of  a  vessel,  where,  under  favourable  circumstances,  they 
begin  to  develop  further,"  that  is  to  say,  they  become  "  chitinous 
cysts  with  fantastic  outlines,"  or  also  "  single-chambered  chitinous 
cysts  "  ;  scolices  may  develop  in  both. 

The  multicular  echinococcus,  which  in  man  produces  a  severe  disease 
and  almost  always  leads  to  premature  death,  settles  most  frequently  in 
the  liver,  but  may  also  be  found  primarily  in  the  brain,  the  spleen  and 
the  supra-renal  capsule  ;  by  means  of  metastasis  it  may  reach  the  most 
various  organs  from  the  liver,  especially  those  of  the  abdomen,  but  also 
the  lungs,  the  heart,  &c.  Hitherto  235  cases  have  been  described,  being 
70  from  Russia,  56  from  Bavaria,  32  from  Switzerland,  30  from  the 
Austrian  Alps,  25  from  Wiirtemburg  ;  the  remaining  cases  are  distributed 
over  Central  Germany,  Baden,  Alsace,  France,  Upper  Italy,  North  America  ; 
in  some  the  origin  is  doubtful  ;  in  any  case  after  Russia,  the  mountainous 
South  of  Europe  is  the  principal  region  of  distribution.  As  to  the  domesticated 


1  This  may  perhaps  be  explained  by  the  fact  that  the  hosts  are  slaughtered 
before  the  parasites  have  attained  the  size  or  other  conditions  necessary  to 
disintegration. 


260  THE   ANIMAL    PARASITES   OF   MAN 

animals,  the  same  parasite  is  found  principally  in  the  ox  (according  to 
Meyer,  in  Leipzig  7  per  cent,  of  the  oxen  there  are  affected  with  echinococcus)  ; 
it  is  rarer  in  the  sheep  and  very  scarce  in  the  pig. 

It  has  already  been  mentioned  above  that  recently  the  multi- 
locular  echinococcus  has  been  stated  to  be  specifically  different 
from  hydatid  or  unilocular  echinococcus  ;  this  view  is  supported 
by  experimental  feedings  with  the  multilocular  bladder- worm. 
These  experiments  were  first  undertaken  by  Klemm  (1882)  on  dogs  ; 
this  author,  however,  obtained  taenise  which  were  not  distinct 
from  the  typical  T.  echinococcus ;  Vogler,  Mangold  and  Miiller,  on 
the  other  hand,  report  that  the  taenia  reared  in  their  experi- 
ments exhibited  differences  in  the  form  of  the  booklets  as  well  as 
in  the  distribution  of  the  ova  within  the  terminal  proglottides  ; 
no  weight,  however,  can  be  laid  on  these  two  circumstances, 
because  these  conditions  vary  in  T.  echinococcus.  More  important 
is  the  fact  that  Mangold,  who  fed  a  young  pig  with  onco- 
spheres  of  tcenia  reared  from  the  multilocular  echinococcus, 
found  two  growths  in  its  liver  four  months  later,  and  these  were 
recognised  as  Echinococcus  multilocularis  ;  nevertheless  chance  may 
have  favoured  him,  and  thus  this  question  has  remained  undecided 
until  the  present  time. 

LITERATURE. 

SIEBOLD,   C.   TH.     v.    Ueb.  d.  Verw.  v.  Echinococcusbrut   in  Taenien.     (Z.  f.   w.  Z., 

1853,   iv.f   p.   409.) 

ESCHRICHT,    T.    F.     Om    the   hydatider.     (Ov.    Kgl.    Dansk.    Vidensk.    Selsk.    Forh., 

1853,   p.   211  ;    1856,  p.    127  ;   Zeitschr.   f.   d.   ges.   Naturw.,    1857,   x->   P-   23T-) 

LEUCKART,   R.     Ueb.    Echinococcus.     (Gott.   Nachr.,    1862,   p.    13,   and   in   his   book 

on  Parasites.) 
NAUNYN,    B.     Entw.    d.    Echinococcus.     (Arch.    f.    An.    u.    Phys.,     1862,    p.    612  ; 

1863,    pp.    412   and   417.) 
KRABBE,     H.     Die    isl.     Echinococcen.     (Virchow's    Arch.,     1863,     xxvii.,     p.     225  ; 

Dtsch.   Zeitschr.   f.   Thiermed.,   xvii.) 
NEISSEK,   A.     Die  Echinococcen- Krankh.     Berlin,    1877. 
KLEMM,    H.     Z.    Kenntn.    d.    Ech.    multiloc.    der   Leber.     (Bayr.    Aerzte-Intelligenz- 

blatt,    1883,   xxx.,   p.    451  ;    also  in   In.-Diss.   Mi'mchen.) 
THOMAS,  .J.    D.     Hydatid   disease     ...     in   Australia.     Adelaide.    1884. 
MADELUNG,    O.    W.     Beitr.    meckl.    Aerzte    7.    Lehre  v.    d.    Echinococcen- Krankh., 

Stuttg.,   1885. 

VIERORDT,    H.     Abh.    iib.    d.    multilocnlaren   Echinococcus.     Freiburg,    1886. 
LENDENFELD,    R.     Taenia   echinococcus.     (Zool.    Jahrb.,    1886,    i.,    p.    409.) 
LEBEDEW,    A.     J.,    and    N.    J.    ANDREJEW.     Transpl.    v.    Echin.    v.    Menschen    auf 

Kaninchen.      (Arch.    f.   path.   An.,    1889,   cxviii.,   p.    552.) 
GUILLEBEAU,    A.     Zur    Hist.    d.    mult.    Ech.      (Arch.   f.    path.    Anat.,     1890,    cxix., 

p.    108.) 
ERLANGER,    R.    v.    D.    Geschlechtsapp.    d.    T.    ech.     (Ztschr.    f.    w.    Zool.    L.,    1800, 

P-    555-) 
OSTERTAG,    R.     Ueb.    d.   Ech.    multil.    bei    Rind.    u.   Schwein.      (Dtsch.    Zeitschr.    f. 

Thiermed.,    1891,   xvii.,  p.    172.) 
MANGOLD,     Ueb.   d.   multil.    Ech.  u,.   seine   Taenia.     (Berl.   klin.   Wochenschr.,    1892. 

No.   2  ;   also  In.-Diss.  Tubingen,   1892.) 


NEMATODES  261 

MULLER,    A.     Beitr.    z.    Kenntn.,    d.  T.    echin.     (Munch,    med.    Wochenschr.,    1893, 

No.    13.) 

PEIPER.     Verbr.   d.   Ech.-Krankh.    in   Vorpommern.,    Stuttg.,    1894. 
WIEDEMANN,  C.     Z.  Statist,   d.    Ech.-Krankh.   in  Vorp.  In.-Diss.,    Greifswald,    1895. 
SCHMIDT,  W.     Ueb.    d.    geogr.     Verbr.    d.    Ech.  mult.   u.   hyd.   i.  Bayern.   In.-Diss., 

Miinchen,   1899. 
RIEMANN,    H.     Ueb.   d.    Keimzerstr.    d.    Ech.    im.   Periton.     (Beitr.   zur   klin.    Chir., 

xxiv  ;  also  In.-Diss.,  Rostock,   1899.) 

TSCHOTSCHEL,   K.     Zur  Cas.   d.    Ech.-Krankh.   in   Vorp.     (In.-Diss.,   Greifsw.,    1900.) 
POSSELT,    A.   D.    Geogr.  d,  Verbr.   Blasenwurmleid.,  insb.  d.  Alveolarechin.Tl.  Leber 

seit,    1886.     Stuttg.,    1890. 
MELNIKOW-RASWEDENKOW,   N.     Studien   iib.  d.   Echin.   alveol.   s.   multil.     (Beitr.  z. 

path.   An.   u.   allg.   Path.     [Zeigler],   Suppl.   iv.,   January.    1901.) 

ADDENDUM. 

Tcenia  hominis,  v.  Lstw.,  1902. 

Scolex  measures  1*34  mm.  in  length,  2  mm.  in  breadth.  There  is 
a  rudimentary  rostellum  without  hooks  on  the  apex  ;  the  suckers 
are  deep ;  behind  them  there  is  a  ring-shaped  swelling ;  no 
pigment.  The  neck  is  rn  mm.  in  breadth.  Calcareous  bodies 
very  numerous,  0*013  nun.  in  size.  Genitalia  ?  Only  one  immature 
specimen  has  come  to  our  knowledge,  which  was  found  in 
Aschabad  by  Anger  (C.  f.  Tcenia  asiatica,  p.  233),  (v.  Linstow  in 
C.  f..  B.,  P.  u.  I.,  1902  [I-],  xxxi.,  p.  770). 


C.     NEMATODES,  Thread-worms. 

Nematodes  are  as  a  rule  elongated  round  worms  of  a  filiform  or  fusi- 
form shape  ;  their  length  varies  according  to  the  species  from  about  i  mm. 
to  40-80  cm.  The  outer  surface  of  the  body  is  smooth  or  annulated,  and 
at  certain  points  provided  with  papillae,  occasionally  also  with  bristles  and 
alar  appendices.  The  anterior  end  carrying  the  oral  aperture  is  usually  rather 
slender,  occasionally  quite  thin  ;  the  posterior  end  is  pointed  or  rounded  ; 
the  anus,  as  a  rule,  lies  somewhat  in  front  of  the  posterior  extremity. 
The  sexes  are  almost  always  separate,  and  the  male  can  as  a  rule  be 
easily  distinguished  from  the  female  because  the  former  is  smaller  and  more 
slender,  its  posterior  extremity  is  often  spiral  or  incurvated,  or  carries  an 
alar  appendix,  whereas  the  female  is  larger  and  thicker,  and  its  posterior 
extremity  is  straight.  In  the  male  the  genitalia  open  into  the  anus  ;  the 
sexual  orifice  of  the  female  opens  ventrally  along  the  median  ridge  in  the 
anterior  half  of  the  body,  in  the  middle,  or  a  Little  further  back.  Both 
sexes,  moreover,  have  an  orifice,  the  excretory  pore,  which  is  situated  ventrally 
along  the  median  ridge  and  fairly  near  the  anterior  extremity. 

In  large  species,  even  with  the  naked  eye,  two  lighter  transparent 
stripes — the  lateral  ridges — may  be  distinguished  ;  they  run  along  the  sides 
of  the  body  from  the  anterior  to  the  posterior  end,  while  two  other  stripes } 
the  median  ridges,  running  along  the  ventral  and  dorsal  median  ridges  are 
less  evident  ;  in  exceptional  cases  there  are  also  four  sub-median  ridges. 


262  THE   ANIMAL   PARASITES    OF    MAN 

Some  nematodes  live  free  in  fresh  or  salt  water,  in  soil,  mud,  or  decaying 
vegetable  matter,  others  parasitically  in  the  most  various  organs  of  animals, 
as  well  as  frequently  also  in  plants. 

(a)  ANATOMY  OF  THE  NEMATODES. 

All  the  Nematodes  are  covered  by  a  CUTICLE,  which  in  the 
small  species  is  thin  and  delicate,  while  in  the  larger  species  it 
is  thickened,  and  may  consist  of  several  layers  of  complicated 
structure.1  Porocanals  do  not  occur.  According  to  general  opinion, 
which  is  confirmed  by  the  history  of  development,  the  cuticle  is  a 
product  of  the  epithelium  that  had  formerly  existed  or  is  still  found 
beneath  it  ;  in  young  specimens  and  small  species  it  is  perceptible, 
but  in  older  worms  it  frequently  alters  so  considerably  that  not  only 
do  the  borders  of  the  cells  disappear,  but  a  fine  fibrous  differentia- 
tion appears  in  the  plasm.  The  matrix  or  hypodermis  then  has  the 
appearance  of  a  connective  tissue  strewn  with  nuclei,  so  that  it 
is  hardly  distinguishable  from  the  texture  of  the  cutis,  which  is 
always  present,  though  it  may  be  but  feebly  developed.2  It  is 
the  cutis  alone  which  projects  crest-like,  and  which  forms  the 
above-mentioned  lateral  and  median  ridges  (fig.  182). 

Unicellular  cutaneous  glands  are  known  in  parasitical  as  well 
as  in  free  living  species  ;  they  vary  in  number  and  arrangement, 
and  are  found  discharging  some  at  the  anterior  extremity,  and 
others  in  the  vicinity  of  the  genital  orifices.  In  other  cases  large 
numbers  of  them  are  present  along  the  lateral  ridges  ;  they  are 
strongly  developed  in  most  of  the  Trichotrachelidae,  where  they 
discharge  either  along  a  part  of  the  ventral  surface  or.  along  the 
lateral  and  median  ridges  ;  they  are  placed  so  closely  together  that  the 
ridges  of  the  cuticle  perforated  by  the  orifices  have  long  been  known, 
and  have  been  described  as  "  rodlet  borders,"  or  "  fields  of  rods."3 

As  the  cutis  is  immediately  adjacent  to  the  dermo-nmscular  tube, 
the  simple  layer  of  the  muscular  cells  is  by  the  longitudinal  ridges 


1  Bommel,  A.  v.,  "  Ueber  die  Cuticularbildung  bei  Nemat."  (Arb.  zool.-zoot.  Instil. 
Wiirzburg,  1895,  x->  P-  189.)  Toldt,  C.,  "  Ueber  den  feinen  Bau  der  Cuticula  bei  Ascaris 
megalocephala  "  (Arb.  aus  d.  zool.  Inst.  Wien.,  1899,  xi.,  p.  289). 


-  The  subcuticular  stratum  of  the  nematodes  certainly  requires  further  investiga- 
tion. L.  Jammes  considers  it  nervous  ("  Contrib.  d  I' etude  de  la  couche  sous-cuticu- 
laire  des  Nemat."  An.  sc.  nat.  Zool.,  1892,.  Ser.  vii.,  vol.  xiii.,  p.  321),  and  M. 
Condorelli-Francaviglia  does  not  find  the  hypodermis  cells  in  epithelium-like  order,  but 
separated  by  a  granular-fibrillary  mass,  which  entirely  resembles  the  substance  of 
the  deeper-lying  layers  of  the  cuticle  ("  Ric.  zool.  ed.  anat.-ist.  sulla  Filaria  labiata," 
Boll.  soc.  rom.  stud,  zool.,  1895,  iv->  PP-  93  and  248). 

3  Jagerskiold,  L.  A.,  "  Weit.  Beitr.  z.  Kenntn.  d.  Nemat."  (Kgl.  Sv.  Vet.-Ak.  Handl., 
1901,  xxxv.,  No.  2.) 


ANATOMY  OF  THE   NEMATODES 


263 


divided  into  four  quadrants — two  dorsal  and  two  ventral.  The 
elements  of  the  dermo-muscular  tube  are  in  the  simplest  cases  large, 
rhomboid  cells,  that  lie  two  by  two  in  each  quadrant,  so  that  on 
transverse  section  of  the  entire  worm  only  eight  cells  are  per- 
ceptible. The  outer  border  of  the  cells  is  converted  into  fibrils, 
while  the  contiguous  inner  portion  has  remained  protoplasmatic,  and 
contains  the  nucleus.  In  large  species  the  muscular  cells  do  not 
only  increase  in  length  (up  to  3  mm.)  and  in  number  in  every 
quadrant,  but  their  contractile  portion  bends  groove-like  (fig.  182), 


FIG.  182. — Diagram  of  a  transverse  section  of 
Ascaris  lumbricoid.es,  about  50/1.  The  flat  intestine 
is  in  the  middle,  and  to  the  right  and  left  near 
it  within  the  wall  of  the  body  the  lateral  ridges 
with  excretory  vessel  and  lateral  nerves,  above 
and  below  in  the  centre  the  dorsal  or  ventral 
median  ridges  with  the  nerves  radiating  to  the 
muscles  (after  Brandes). 


FIG.  183. — Anterior 
end  of  an  Ascaris  mega- 
locephala  cut  open  and 
showing  the  four  tuft- 
like  organs  lying  on  the 
lateral  ridges,  natural 
size  (after  Nassonow.) 


thereby  even  becoming  larger  ;  simultaneously  space  is  gained  for 
more  cells,  the  protoplasmatic  parts  of  such  cells  (on  transverse 
section)  hang  out  of  the  grooves  like  vesicles.  In  all  cases  there 
is  only  one  layer  of  longitudinal  muscular  cells,  which  by  con- 
tracting can  shorten  the  body,  .or  by  contracting  one  side  can 
bend  it.  In  the  latter  case  the  muscles  of  the  opposite  side 
have  an  antagonistic  effect,  in  the  former  the  elasticity  of  the 
cuticle  acts  in  the  same  way. 


264  THE    ANIMAL    PARASITES    OF    MAN 

The  BODY  CAVITY,  which  lies  between  the  body  and  intestinal 
walls,  is  according  to  its  development  not  a  coelom  but  the  cleavage 
cavity.  It  is  considerably  restricted  by  the  protoplasmatic  por- 
tions of  the  muscular  fibres  and  by  the  genitalia  ;  it  contains  a 
small  quantity  of  haemolymph,  and  sometimes  also  leucocytes. 

We  may  now  consider  the  "  tuft-like  "  or  "  phagocytic  organs," 
which  attain  i  cm.  in  size,  and  consist  of  four,  six,  or  even 
more  ramified  cells,  which  lie  close  to  the  walls  of  the  body 
(fig.  183).  They  are  found  either  only  in  the  anterior  part  of 
the  body  (Ascaris),  or  extend  the  whole  length  of  the  body 
(Sclerostomum,  Strongylus),  and  their  position  usually  corresponds 
to  the  lateral  ridges.  In  some  species  there  are  small  proto- 
plasmatic cells  at  their  processes.  In  consequence  of  their  size 
they  can  be  recognised  with  the  naked  eye,  especially  when  loaded 
with  granules  of  stain  (carmine,  Indian  ink)  injected  into  the 
body  cavity.1 

INTESTINAL  CANAL.  The  oral  aperture,  which  is  situated  at  the 
tip  of  the  anterior  extremity,  is  frequently  surrounded  by  thick 
lips,  or  small  bristles,  or  papilla?  ;  it  leads  to  a  more  or  less 
strongly-developed  oral  cavity,  which  is  lined  by  a  continuation 
of  the  body  cuticle,  and  which  in  some  species  is  provided  with 
"  teeth,"  representing  differentiated  portions  of  the  cuticle. 

THE  (ESOPHAGUS  (fig.  184),  which  arises  from  the  base  of  the 
oral  cavity,  is  as  a  rule  a  short,  bottle-shaped  tube,  its  wall  is 
chiefly  composed  of  radiating  muscular  fibres,  which  give  it  the 
appearance  of  being  transversely  striped.  The  radiary  fibres  cause 
a  dilatation  of  the  lumen,  and  exercise  an  effect  antagonistic  to 
the  elasticity  of  the  cuticle  lining  the  inner  surface.  The  latter 
has  its  own  particular  layer,  which  is  not  in  direct  connection 
with  that  of  the  oral  cavity.  The  posterior  end  of  the  oesophagus 
presents  a  bulb-like  dilatation,  and  is  frequently  provided  with 
small  teeth.  In  a  few  forms,  which  belong  to  the  family  of  the 
Trichotrachlidse  (Trichocephalus,  Trichinella),  the  oesophagus  is  a 
very  long  cuticular  tube,  beset  on  its  dorsal  surface  with  a  series 
of  large  nucleated  cells.  In  others  (Cucullanus,  a  few  species  of 
Ascaris,  &c.),  a  tube,  the  so-called  glandular  stomach,  only  lined 
by  epithelial  cells,  follows  behind  the  muscular  oesophagus.  This 
glandular  stomach  is,  from  its  structure,  easily  distinguished  from 


1  Nassonow,  N.,  "  Sur  les  org.  phagocyt.  d.  A  scar."  (Arch,  parasit.,  1898,  i.,  p.  170). 
"  Z.  Kennt.  d.  phagocyt.  Org.  b.  d.  parasit.  Nemat."  (Arch.  f.  mikr.  An.,  1900,  lv.,  p. 
488).  Jagerskiold,  L.  A.,  "  Ueb.  d.  bilschelf.  Org.  b.  d.  Ascaris-arten  "  (C.  f.  B.,  P. 
u.  I.,  1898  [i],  xxiv.,  pp.  737  and  785). 


ANATOMY    OF    THE    NEMATODES 


265 


the  mid-gut,  which  is  likewise  cellular.  The  so-called  mid-gut  is 
a  tube  lined  by  flat,  cubical,  or  cylindrical  cells  (fig.  182),  which 
has  no  outer  mesodermal  layer  (connective  tissue,  muscles) ;  its 
transverse  section  is  circular  or  flattened  dorso-ventrally ;  the 
lumen  may  run  in  a  straight  line,  or  it  may  form  sinuosities 
amongst  the  alternating  prominences  of  the  then  flat  epithelial 
cells. 

The  ectodermal  hind-gut  is,  as  a  rule,  very  short  ;  very  fre- 
quently there  is  no  cellular  lining,  so  that  it  consists  only  of  a 
cuticular  tube,  which  in  large  species  is  surrounded  by  circular 
muscles.  In  some  species  there  are  special  bundles  of  cutaneous 
muscles  along  the  entire  gut,  or  at  least  on  the  terminal  gut. 
There  is  sometimes  a  retrogression  of 
the  alimentary  tube  in  the  adult  stage 
of  a  few  parasitical  species. 

Intestinal  caeca  and  cesophageal  glands 
sometimes  appear  as  intestinal  append- 
ages ;  the  former  are  cylindrical  orgaAs 
of  various  size,  running  backwards  or 
forwards,  and  arising  from  the  posterior 
extremity  of  the  oesophagus.  They  are 
lacking  in  many  species.  The  ceso- 
phageal glands  are  unicellular  ;  a  dorsal 
and  two  subventral  glands  may  be  dis- 
tinguished according  to  their  position  ; 
as  a  rule  they  open  into  the  oesophagus 
at  a  distance  from  one  another.  The 

glandular  body  lies  in  the  bulb  of  the  oesophagus,  the  dorsal  ones 
in  the  cul-de-sac  arising  from  it.1 

THE  NERVOUS  SYSTEM  of  the  larger  species  of  Ascaris  is  the  only 
one  sufficiently  known  ; ''  it  consists  of  a  pharyngeal  ring  con- 
taining 50 — 60  fibres  closely  surrounding  the  oesophagus  (fig.  184), 
various  groups  of  ganglion  cells,  and  a  certain  number  of  nerves 


FIG.  184. — Transverse  sec- 
tion of  anterior  end  of  the 
body  of  Ascaris  lumbricoides 
with  the  nerve  ring  surround- 
ing the  oesophagus.  (Enlarged.) 


1  Jagerskiold,  L.  A.,  "  Beitr.  z.  Kenntn.  d.  Nemat."  (Zool.  Jahrb.  Anat.,  1894,  Part 
vii.,  p.  449).  "  Ueb.  d.  (Esophagus  d.  Nemat."  (Bih.  K.  Svensk.  Vet.-Akad.  HandL, 
1897,  xxiii.-iv.,  No.  5).  Looss,  A.,  "  Ueb.  d.  Ban  d.  (Esoph.  bei  einig.  Ascar."  (C.  /. 
B.,  P.  u.  I.,  1896  [i],  xix.,  p.  5). 

2Biitschli,  O.,  "Beitr.  z.  Kenntn.  d.  Nervens.  d.  Nemat."  (Arch.  /.  mikr.  An.,  1874, 
x.,  p.  74).  "  Zur  Herleitg.  d.  Nervens.  d.  Nemat."  (Morph.  Jahrb.,  1885,  x.,  p.  486). 
Rohde,  E.,  "Beitr.  z.  Kenntn.  d.  Nemat."  (Zool.  Beitr.  [A.  Schneider],  1885,  i.,  p.  n). 
Hesse,  R.,  "  Ueb.  d.  Nervens.  v.  Asc.  megaloceph."  (Z.  f.  w.  Z.,  1892,  liv.,  p.  548). 
Apathy,  St.,  "Das  leit.  Elem.  in  d.  Muskelf.  v.  Ascaris"  (Arch.  f.  mikr.  An.,  1894, 
xliii.,  p.  886).  Brandes,  G.,  "  Das  Nervens.  d.  als  Nemathelm.  zusammengef.  Wurm- 
tyf>."  (Abh.  d.  naturf.  Ges.  Halle.,  1899,  xxi.,  p.  273). 


266 


THE    ANIMAL    PARASITES    OF   MAN 


Exp. 


sp.. 


extending  anteriorly  as  well  as  posteriorly.      The  remarkably  small 
number    of    fibres,    as    well    as    ganglion    cells,    is    characteristic    of 

the  nervous  system  of  all  Nema- 
todes.  Immediately  behind  the 
pharyngeal  ring  (fig.  185,  Lg.)  an 
agglomeration  of  ganglion  cells  lies 
at  either  side  (lateral  ganglia)  ; 
part  of  their  off-shoots  form  the 
pharyngeal  ring,  and  part  are  di- 
rected posteriorly  and  ventrally, 
and  unite  partly  in  front  of  and 
partly  at  the  back  of  the  excretory 
pore,  with  fibres  originating  direct 
from  the  pharyngeal  ring,  and  pass- 
ing along  the  ventral  median  ridge 
to  the  back,  these  fibres  then  to- 
gether form  the  ventral  median 
nerve  (fig.  185  V.m.n.).  This  nerve, 
originally  consisting  of  thirty  to 
fifty  fibres,  becomes  attenuated  in 
the  female  quite  evenly  in  its 
further  course.  There  is  also  an 
agglomeration  of  ganglion  cells  close 
in  ffont  of  the  anus  (anal  ganglia), 
and  then  the  median  nerve  divides 
in  order  to  combine  with  the  lateral 
nerves  on  either  side.  In  the  male 
the  median  nerve  enlarges  to  nearly 
the  original  number  of  fibres  in 
front  of  the  anal  ganglion,  which 
contains  seven  cells  ;  there  is  also 
an  anal  ring  embracing  the  terminal 
gut,  and  there  are  two  ganglion  cells 
in  it  on  each  side.  In  the  dorsal 
median  ridge  the  dorsal  median  nerve 
is  alike  in  both  sexes ;  arising  in 
front  with  a  single  root  from  the 
pharyngeal  ring  it  gathers  its  fibres 
from  the  lateral  ganglia  ;  in  the 
anterior  part  of  the  body  it  con- 
sists of  thirteen  to  twenty  fibres  ; 
in  the  posterior  part  of  the  body  the  fibres  are  reduced  to  four 


V.m.n.. 


A.- 


FIG.  185. — Schematic  representation 
of  the  nervous  system  of  a  male, 
Ascaris  megalocephalus  (after  Brandes) 
A.,  Anus;  Ag.t  Anal  ganglion;  C., 
Commissures  ;  D.m.n.,  dorsal  median 
nerve  ;  Exp.,  excretory  pore  ;  Pr., 
pharyngeal  ring  ;  Lg. ,  lateral  ganglia  ; 
Ln.,  lateral  nerve  ;  Sp.,  papilla  of 
sense  ;  V.m.n.,  ventral  median  nerve. 


ANATOMY  OF    THE    NEMATODES  267 

or  six  ;  behind  the  anus  it  divides  and  combines  with  the  lateral 
nerves.  The  latter  consist  of  two  fasciculi  at  either  side  extend- 
ing to  the  hindermost  part — one  dorsal  and  one  ventral — which  in 
the  greatest  part  of  the  body  do  not  run  in,  but  next  to,  the 
lateral  ridges,  and  exhibit  a  different  origin  in  the  front.  The 
ventral  fasciculus  at  each  side  branches  off  from  the  ventral 
median  nerve  in  front  of  the  excretory  pore,  whereas  the  dorsal 
fasciculi  originate  from  the  pharyngeal  ring  close  to  the  lateral 
ganglia.  Each  of  the  four  fasciculi  contains  only  two  or  three 
fibres,  which  run  backwards  parallel  to  the  lateral  ridges  ;  a  few 
centimetres  in  front  of  the  caudal  extremity  they  join  the  lateral 
ridges  and  remain  separate  from  one  another  up  to  the  level  of 
the  anal  ganglion  ;  here  they  amalgamate  on  either  side,  after 
each  interpolating  one  ganglion  cell,  with  the  single  short  lateral 
nerve  which  first  takes  up  the  forked  ends  of  the  ventral,  and  then 
of  the  dorsal  median  nerve  ;  finally,  both  lateral  nerves  unite  with 
each  other  at  the  back  in  arch-like  manner. 

In  the  male  each  ventral  part  of  the  lateral  nerves  becomes 
thickened  by  taking  up  fibres  from  the  ventral  nerves,  which  become 
thickened  posteriorly  to  the  nervus  bursalis,  which  towards  the 
middle  gives  off  a  mass  of  fibres  to  the  "  genital  papillae  "  situated 
in  front  of  and  behind  the  anus  ;  the  number  of  these  fibres 
averages  80 — 100  ;  in  its  further  course  the  bursal  nerve  resembles 
the  corresponding  ventral  part  of  the  lateral  nerves  of  the  female. 

The  ventral  and  dorsal  nerves "  are  connected  by  a  number  of 
semi-circular  commissures,  which  originate  from  the  ventral  nerves 
and  serve  to  supply  the  dorsal  nerve,  which  is  always  being 
decreased  by  fibres  departing  from  it.  It  is  remarkable  that  these 
commissures  are  not  placed  symmetrically,  and  their  position  also 
is  different  in  the  two  sexes  ;  in  the  female  there  are  thirty-one 
on  the  right  side  and  only  thirteen  on  the  left  side.  In  the  male 
there  are  thirty-three  commissures  on  the  right  side  and  fourteen 
on  the  left,  which  run  into  the  sub-cuticular  layer  generally  in 
pairs,  and  usually  cross  at  the  level  of  the  lateral  ridges. 

The  fibres  of  the  two  median  nerves  are  chiefly  motory  ; 
fascicular  processes  run  from  each  protoplasmatic  part  of  the 
muscular  cells  to  the  median  nerves  ;  from  these  they  take  up 
bundles  of  primitive  fibrils,  which  separate,  pass  through  the  proto- 
plasmatic part  and  enter  the  contractile  part  (fig.  182).  One  part 
of  the  fibrils,  however,  penetrates  .  beyond  the  muscles  into  the 
subcuticular  layer,  where  they  form  a  network,  probably  of  a 
sensory  nature,  with  contiguous  fibrils.  Nerves  directed  anteriorly 


268  THE    ANIMAL    PARASITES    OF    MAN 

finally  originate  from  the  pharyngeal  ring ;  they  consist  each  of 
three  fibres,  carry  three  ganglion  cells  at  their  point  of  origin, 
and  enter  the  sensory  organs  of  the  three  papillae  surrounding  the 
oral  aperture.  Two  of  these  little  trunks  lie  in  the  lateral  ridges, 
the  remaining  four  are  situated  in  the  middle  of  the  four  quad- 
rants (Nn.  submediani  anteriores). 

The  parasitical  species  lack  higher  ORGANS  OF  SENSE  ;  free- 
living  worms  occasionally  have  two  rust-red  eyes,  sometimes  witli 
lenses,  at  the  front  of  the  body.  In  addition  to  the  above- 
mentioned  sensory  papillae  surrounding  the  oral  aperture  and  the 
genital  papillae  of  the  male  at  the  end  of  the  body,  the  Ascarides 
possess  still  another  pair,  situated  in  the  vicinity  of  the  lateral 
ganglia  of  the  "  cervical  papillae  "  ;  they,  moreover,  possess  two 
dorsal  papillae  in  the  central  region  of  the  body  and  two  lateral 
ones  near  the  tip  of  the  tail. 

THE  EXCRETORY  ORGANS  of  the  Nematodes  are  variable.  In  a 
great  many  cases  the  apparatus  is  symmetrical,  and  consists  of 
a  tube  commencing  in  the  posterior  extremity  along  each  lateral 
ridge  (fig.  182),  and  passing  towards  the  front.  In  the  vicinity  of 
the  anterior  extremity  both  tubes  pass  out  of  the  lateral  ridges, 
bend  ventrally,  and,  in  the  median  ventral  ridge  unite  into  a  short 
duct,  which  opens  into  an  excretory  pore  (fig.  185,  Exp.),  and  is 
lined  by  a  continuation  of  the  cuticle  of  the  body.  Asymmetry  is 
occasioned  through  the  excretory  duct  proceeding  from  the  ventral 
pore  to  the  left  at  the  lateral  ridge,  and  then  taking  up  the  tube 
in  the  anterior  part,  which  is  broader,  and  passes  along  the  left 
lateral  ridge  ;  shortly  before  its  union  with  the  excretory  duct  it 
throws  out  a  branch  to  the  right  towards  the  lateral  ridge,  which, 
however,  always  remains  weak,  and  passes  posteriorly  into  the 
right  lateral  ridge  ;  a  few  smaller  branches  in  addition  spring  from 
the  left  principal  part.  In  other  species  the  right  branch  is 
completely  suppressed  ;  the  entire  organ  thus  lies  along  the  left 
lateral  ridge,  and  consists  of  the  excretory  duct,  which  occasionally 
opens  quite  in  front  near  the  lips,  as  well  as  the  excretory  canal, 
which  throws  out  a  number  of  lateral  branches. 

This  excretory  portion  is  one  single  elongated,  or  horse-shoe- 
shaped  cell,  with  a  large  nucleus  and  an  intracellular  tubular 
system,  which  is  connected  with  the  excretory  duct  originating 
from  the  outer  surface.  The  so-called  ventral  gland  is  the  only 
excretory  organ  of  marine  Nematodes,  and  probably  represents  a 
primitive  form. 

In  a  number  of  Nematodes  (C  heir  acanthus,  Trichosomum,  Tricho- 


ANATOMY    OF    THE    NEMATODES 


269 


cephalus,  Trichinella,  &c.),  however,  special  excretory  organs  are 
lacking ;  possibly  the  cutaneous  glands,  which  are  in  these  species 
generally  powerfully  developed,  replace  these  organs.1 

SEXUAL    ORGANS.      With    the    exception    of    a    few    species,  the 
Nematodes   are   sexually   differentiated. - 

(a)  FEMALE  SEXUAL  ORGANS.  The  sexual  .orifice  (vulva),  sur- 
rounded by  thick  labia,  is,  as  a  rule,  ventral  and  situated  in  the 
middle  of  the  body,  or  a  little  more  forward,  rarely  further  back.  It 
leads  into  a  short  vagina,  continued  by  the  two  uteri,  which  may  be 
long  or  short  ;  the  long  filiform  ovaries  are  contiguous  to  them 
(fig.  186).  In  smaller  species  one  of  the  uteri,  with  its  ovary, 
extends  towards  the  front,  the  other  towards  the 
back.  In  larger  species  both  the  uteri  and  ovaries 
extend  backwards  (parallel),  the  latter  attaining  a 
considerable  length,  so  that  they  form  many  con- 
volutions in  the  body.  The  entire  apparatus  lies 
within  the  abdominal  cavity,  and  in  some  species 
~7-  (for  instance,  Trichinella)  is  single. 


At  the  blind  end  of  the  ovary  there  is  a  cumulus 
oophorus,  i.e.,  a  mass  of  protoplasm  with  numerous 
nuclei  that  multiply  continuously.  Gradually  the  nuclei 
arrange  themselves  in  longitudinal  rows  (fig.  187)  and 
the  protoplasm  commences  to  leave  the  periphery  and 
surround  each  nucleus.  The  nearer  to  the  uterus  the 
more  progressive  is  this  loosening  process,  until  club- 
shaped  cells  each  containing  a  nucleus  are  developed. 
The  most  slender  end  of  each,  however,  is  still  attached 
to  an  axial  fibre  of  protoplasm,  the  rhachis  ;  probably 
this  has  some  connection  with  the  nutrition  of  the  ova. 
Finally  the  ova  fall  off  and  reach  the  uterus,  where 
they  are  fertilised  and  enclosed  in  shells. 

(b)  MALE  SEXUAL  ORGANS.  There  is  never 
more  than  one  testis  (fig.  188),  which  is  a 
straight  or  sinuous  tube  of  the  same  con- 
struction as  an  ovary,  and  in  which  the  sper- 
matic spore  capsules  originate  in  the  same  manner 
as  the  ova.  In  the  same  way  as  the  ovarv 


Ov. 


FIG.  1 86.  —  Cen- 
tral part  of  the  body 
of  the  rhabditis 
form  '  of  Rhabdo- 
nema  nigrovenosum 
with  female  geni- 
talia  lying  on  its 
side.  (Magnified.) 
/.,  intestine;  G., 
genital  orifice  (vul- 
va) ;  Ov.,  ovarium  ; 
lit.,  uterus. 


1  Jagerskiold,  L.  A.,  "  Beitr.  7.  Kenntn.  d.  Nemat."  (I.e.)  "  Biischclf.  Org.  b.  Asc." 
(I.e.)  "  Weit.  Beitr.  z.  Kenntn.  d.  Nemat."  (I.e.).  Hamann,  O,  "  Die  Nemathelm.,  II.,  Jena, 
1895.  Nassonow,  N.  (I.e.).  Cobb,  N.  A.,  "  Oxyuris-laYua;  hatch,  in  the  hum.  stow." 
(Proc.  Linn.  Soc.,  N.  S.  Wales,  1891  [2],  v.,  p.  168),  and  other  authors. 

'Nedkoff,  P.,  "  Ueb.  d.  Metamorph.  d.  Geschlechtsapp.  b.  Ascar.  nigroven.,  In.-Diss. 
Leipzig,  1897. 


270 


THE    ANIMAL    PARASITES    OF    MAN 


passes    into    the    uterus,    so    does    the    testis    pass    into     the    sper- 
matic  duct  ;   the  latter  is   often  divided  into  the  somewhat  dilated 

seminal  vesicle  and  into  the  mus- 
cular ductus  ejaculatorius,  which, 
running  ventrally  from  the  intes- 
tine backwards  (fig.  189),  finally 
opens  into  the  hind  gut.  The  sper- 
matozoa of  the  Nematodes,  it  may 
be  noted,  only  attain  their  full 
development  after  the  sperm- 
mother  cells  have  been  conveyed 
by  copulation  into  the  uteri  of  the 
female  genitalia.  The  spermatic 

corpuscles  of  the  Nematodes  present  an  unusual  form.     (They  have 
no  flagella  but   are  capable  of  amoeboid  movement.) 


FIG.  187.  —  Transverse  section 
through  the  ovarian  tube  of  A  scar  is 
mystax  (of  the  cat)  at  various  levels. 
To  demonstrate  the  development  of 
the  ova  and  of  the  rhachis.  (Mag- 
nified.) 


FIG.  1 88.— Male  of 
the  rhabditis  form  of 
Rhdbdonema,  nigrovcno- 
sum  (magnified).  A., 
anus  ;  /.,  small  in- 
testine ;  T.,  testicu- 
lar  tube  ;  O.,  oral 
orifice ;  P.,  papilla  ; 
Sp.,  spicula. 


FIG.  189. — Transverse  section  through 
the  posterior  extremity  of  the  body  of 
A  scans  lumbricoid.es  (Male).  The  intestine 
is  in  the  middle,  and  the  lateral  ridges 
are  subjoined  thereto  ;  above  the  intes- 
tine the  two  spicula  sacs  are  seen  ;  below 
is  the  ductus  ejaculatoris.  The  muscular 
fibres  are  between  the  lateral  and  dorsal 
median  ridges.  (Magnified.) 


The  male  genital   apparatus   is   also   provided  with  one   or  two 
glandular   sacs,   situated   on   the   dorsal   side   of  the   intestine,    and 


DEVELOPMENT   OF    THE    NEMATODES  271 

connected  with  the  cloaca.  In  each  glandular  sac  there  is  a 
chitinous  rod-like  formation,  the  spiculum.  A  special  muscular 
apparatus,  consisting  of  protractors  and  retractors,  causes  the 
movement  of  the  spicula  ;  they  can  be  projected  from  the  cloacal 
orifice  (anus)  during  copulation,  and  when  they  are  introduced 
into  the  vagina  they  serve  as  clinging  organs,  perhaps  also  as 
stimulatory  organs. 

The  male  Strongyloides  possess  two  wing-like  appendices  at  their 
posterior  extremity  ;  these  are  projections  of  the  body  wall  sup- 
ported by  so-called  ribs.  This  formation,  most  unsuitably  termed 
bursa  copulatrix,  serves  as  an  organ  of  prehension  during  copula- 
tion. Some  forms,  moreover,  carry  a  suctorial  disc  at  the  pos- 
terior extremity ;  in  others  (Trichinella),  the  spicula  and  other 
clinging  organs  are  absent ;  they  are  then  replaced  by  an  evertable 
cloaca. 

(b)  DEVELOPMENT  OF  THE  NEMATODES. 

This  is  not  the  place  to  describe  minutely  the  well  known 
processes  of  the  fertilisation  and  development  of  the  ova  of  the 
Nematodes.  It  may,  however,  be  briefly  mentioned  that  fertilisa- 
tion always  takes  place  within  the  uterus,  and  that  then  the  eggs 
are  surrounded  by  a  thick  or  thin  shell,  to  which  may  be  added 
an  albuminous  mass,  secreted  by  the  epithelial  layer  of  the  uterus. 
The  shape  of  the  completed  eggs  is  characteristic  of  the  different 
species,  and  therefore  a  single  egg  often  suffices  to  diagnose  the 
species.  According  to  the  species,  the  eggs  may  be  deposited 
sooner  or  later,  either  before  or  during  segmentation,  or  with  the 
embryo  perfectly  developed.  Only  a  few  species  are  viviparous  ; 
in  the  other  Nematodes  the  further  development  of  the  extruded  eggs 
takes  place  after  various  length  of  time  in  the  open,  in  moist 
earth,  or  in  water.  Thick  shelled  eggs  can  maintain  their  develop- 
mental capacity  for  a  long  time,  even  after  prolonged  desiccation. 

Finally,  a  Nematode-like  embryo  develops,  which  usually  lies 
somewhat  coiled  up  within  the  shell,  and  varies  in  its  further 
development  according  to  the  species  to  which  it  belongs. 

In  the  simplest  forms,  as  in  the  free-living  Nematodes,  the 
embryos,  apart  from  their  size,  resemble  their  parents,  and  are 
fully  developed  after  leaving  the  egg  shell.  In  many  parasitical 
Nematodes,  however,  the  young  must  be  called  larvae,  as  they 
present  characters  which  are  subsequently  lost. 

The  manner  of  conveyance  of  the  larval  Nematodes  from  the 
Open — which  they  have  almost  always  attained  from  the  body 
of  the  host — into  the  definitive  host  is  very  different  in  the  various 


272 


THE    ANIMAL    PARASITES    OF    MAN 


species.  In  many  the  conveyance  into  the  definitive  host  is  effected 
direct  after  the  larvae  have  developed  within  the  eggs  ;  thus,  for 
instance,  the  feeding  of  suitable  animals  with  the  embryo-containing 
eggs  of  species  of  Trichocephalus  and  Ascaris,  leads  to  the  settle- 
ment of  the  worms  in  the  intestine  ;  for  the  young  Trichocephali 
or  Ascarides  only  leave  the  egg  shell  when  they  have  attained  the 
intestine  of  the  final  host,  in  which  they  become  adult. 

In  other  cases  (Dochmius,  Sclerostomum,  Strongylus,  &c.),  the 
larvae  hatch  in  the  open,  and  live  for  a  time  free  in  another  shape  ; 
they  grow,  cast  their  skin,  and  finally  gain  the  intestine  of  the 

host  by  means  of  water  or 
some  other  vehicle,  when  they 
lose  their  larval  characters  and 
assume  the  structure  of  the 
parents. 

Frequently,  however,  the 
larvae  of  Nematodes  make 
use  of  one  or  even  two  inter- 
mediary hosts  ;  their  condition 
then  resembles  that  of  Ces- 
todes  or  Trematodes,  except- 
ing that  there  is  never  a 
multiplication  within  the  in- 
termediary hosts.  The  larvae 
become  encapsulated  amongst 
the  tissues  of  the  intermediary 
host,  and  wait  till  they  are 
introduced  with  the  latter  into 

FIG.    190.  — A    piece    of    the   trunk    mus-      the    final    hosti       For   mstance, 
cular     system     of  tthe     pig    with     capsules 
containing   trichinae    (magnified).  OllulcinilS     tricUSplS,     the    adult 

form    of    which    is    found     in 

cats,  lives  previously  encysted  in  the  muscular  system  of  mice. 
Cucullanus  elegans,  which  attains  the  adult  stage  in  fishes  (Perch, 
&c.),  is  found  encysted  in  species  of  Cyclops. 

!J Peculiar  conditions  prevail  in  Trichinella  spiralis.  This  species, 
which  in  its  adult  state  lives  in  the  intestine  of  man  and  of 
various  mammals,  is  viviparous  ;  the  young  Trichinae,  however, 
do  not  leave  the  intestine,  but  attain  the  intestinal  wall  (Cerfon- 
taine,  Askanazy).  The  female  intestinal  Trichinae  bore  themselves 
into  the  intestinal  wall,  where  they  are  found  within  the  sub- 
mucosa,  or  in  the  lumen  of  the  dilated  lacteal  vessels.  Here  the 
young  are  born,  within  the  intestinal  wall,  and  leave  this  posi- 


DEVELOPMENT    OF    THE    NEMATODES  273 

tion  with  the  lymph  stream.  Some  of  them,  no  doubt,  actively 
bore  through  the  intestinal  wall,  likewise  attaining  the  lymph 
stream  or  blood  circulation,  or  even  pass  into  the  body  cavity. 
What  occurs  during  their  further  migrations  is  difficult  to  say  at 
present.  It  has  hitherto  been  maintained  that  the  wandering  is 
entirely  active  ;  for  instance,  the  ligaturing  of  an  artery  would  be 
no  protection  against  the  part  of  the  body  supplied  by  such 
artery  being  invaded  by  Trichinella.  This  observation  cannot  be 
otherwise  explained  than  by  the  active  progress  of  the  young  Trichi- 
nella. The  question,  however,  may  be  mooted  as  to  where  and 
when  the  worms  quit  the  lymphatic  system  and  the  circulation 
of  the  blood  to  wander  further  independently,  and  ultimately 
reach  the  muscular  system,  in  which  they  become  encysted  (fig. 
190).  Thus  the  progeny  does  not  leave  the  body  of  the  host 
inhabited  by  the  parents,  as  is  generally  the  case  amongst  hel- 
minths, but  uses  it  as  an  intermediary  carrier  to  reach  another 
host,  which  is  then  the  final  host.  The  latter  may  belong  to 
another  species,  or  may  be  another  individual  of 'the  same  species. 
This  second  migration  is,  of  course,  purely  passive. 

In  a  number  of  Nematodes,  however,  HETEROGOXY  occurs. 
This  term  signifies  that  manner  of  development  in  which  two 
differently  structured,  sexual  generations  alternate  with  each  other 
within  the  same  species.  To  these  appertains,  for  instance,  Rhab- 
donema  nigrovenosum,  which  lives  in-  the  lungs  of  frogs  and  toads  ; 
this  creature  measures  about  i  cm.  in  length  and  is  hermaphroditic 
(protandric).  The  eggs  are  deposited  in  the  pulmonary  cavity,  and 
through  the  cilia  of  the  same  reach  the  oral  cavity,  where  they  are 
swallowed  and  thus  conveyed  into  the  intestine.  They  pass  through 
the  entire  gut,  and  are  finally  evacuated  with  the  faeces  ;  often,  indeed, 
the  young  themselves  emerge  from  the  egg-shell  within  the  hind  gut 
of  the  frogs.  These  young  forms  are  sexually  differentiated,  remain 
much  smaller  than  the  parent,  their  oesophagus  is  differently  con- 
structed (rhabditis  form),  and  they  are  not  parasitical  (fig.  188). 
After  having  grown  in  the  open  they  copulate  ;  the  males  die  off 
soon  after  copulation,  and  the  females  in  their  own  body  develop 
a  few  young,  which,  given  the  opportunity  to  get  into  frogs,  settle 
in  them,  and  are  transformed  into  hermaphroditic  rhabdonema.  The 
same  manner  of  development  occurs  in  other  species  of  the  same 
genus. 

Finally,  it  must  be  mentioned  that  some  forms  classified  with 
the  Nematodes  (Mermis,  Gordius)  are  only  parasitical  during  the 
18 


274  THE   ANIMAL    PARASITES    OF    MAN 

larval   stage  (in  insects),  and  when  adult  live  free  in    moist  soil,  or 
in  water. 

(c)  CLASSIFICATION  OF  THE  NEMATODES. 

The  Nematodes   are   usually  divided  into   a   number  of   families,  amongst 

which   a    few   aberrant   groups    are   included.     Although   there    are  objections 

to  such  a  classification  it  is  here  maintained  for  practical  reasons  : — 

Fam.   i.      EnoplidcB  consists  only  of  free  species  usually  inhabiting  the  sea. 

Fam.  2.      AnguillulidcB,  Nematodes,  most  of  which  live  free  in  fresh  water, 

in  soil,  or  in  macerating  substances  ;  amongst  them  there  are  some  which 

live   parasitically   on  plants,   more  rarely   on   animals.      They   are,   as   a 

rule,   very   small,    and    are    particularly    distinguished    by    the    fact    that 

their  oesophagus  possesses  a  double  dilatation  ;   many  are  provided  with 

a  chitinous  spine  or  with  teeth  in  the  oral  cavity.      The  males  possess 

two  spicules,      sometimes    also    a    bursa    copulatrix  ;    the  females    have 

pointed  tails,   the  vulva  is  situated  in  the  middle  of  the  body  (Anguil- 

lula,   Rhabditis,  Heterodera,   &>c.~). 

Fam.  3.      A ngioslomidce ,  characterised    by   heterogony    (Rhabdonema,    Angios- 

toma,    Allantonema,    <S>c.). 

Fam.  4.  Gnathostomida,  a  small  family  only  comprising  the  genus  Gnatho- 
stoma  s.  Cheir acanthus,  the  members  of  which  live  in  the  stomach  of 
vertebrates,  especially  mammals  ;  recognisable  by  numerous  ramified 
spines -which  cover  either  the  whole  body  or  only  the  anterior  part. 
Fam.  5.  Filariidce,  very  long  filiform  Nematodes,  the  oral  aperture  of 
which  is  often  surrounded  by  papillae  or  by  two  lips  ;  the  oesophagus 
is  slender  and  without  bulb  ;  the  male  has  one  or  two  uneven  spicules ; 
the  vulva  is  usually  situated  in  the  anterior  half  of  the  body  ;  generally 
ovoviviparous  (Filaria,  Spiroptera,  Dispharagus,  <S-c.). 

Fam.  6.  Trichotrachelidce ,  recognisable  by  the  oesophagus,  which  resembles 
a  necklet  of  pearls  ;  the  anterior  paf  t  of  the  body  is  usually  of  thread- 
like slenderness,  the  posterior  part  of  the  body,  which  contains  the 
genitalia,  is  more  or  less  thickened  ;  there  may  be  no  spicules  or  only  one. 
There  is  a  single  ovary  ;  vulva  situated  at  the  border  line  between 
the  anterior  and  posterior  parts  of  the  body  (Trichinella,  Tricho- 
cephalus,  Trichosoma,  cS-c.). 

Fam.  7.  StvongylidcB ,  a  very  large  group  divided  into  several  sub-families  ; 
it  is  characterised  by  the  possession  of  six  oral  papillae  ;  the  male 
possesses  a  bursa  copulatrix  and  one  or  two  spicules  at  the  posterior 
extremity  ;  species  usually  small  (Eustrongylus ,  Strongylus,  Syngamus, 
Sclerostoma,  Ankylostoma,  Dochmius,  &c.}. 

Fam.  8.  Ascaridce.  Mouth  with  three  papillae,  one  dorsal  and  two 
ventral  ;  oesophagus  with  bulb  ;  one  or  two  spicules  ;  ovary  double 
(Ascaris,  Oxyuris,  Heterakis.}  «, 

Addendum. — Gordiacea,  greatly  elongated  Nematodes,  which,  in  the  larval 
stage,  live  parasitically  in  insects,  but  in  their  adult  condition  are  free 
living ;  they  have  no  lateral  ridges  and  no  spicules  ;  the  posterior  extremity 
of  the  male  is  bifurcated  ;  two  testes  ;  the  male  and  female  generative 
organs  open  through  the  anus.  The  intestine  is  partly  obliterated.  (Gor- 
dius,  Mermis,  <§•>£.)• 


RHABDITIS  PELLIO1  275 

THE  NEMATODES  OBSERVED  IN  MAN. 
(a)  Fam.  Anguillulidce. 

Gen.  i.      Rhabditis,  Du  jar  din,  1845. 

Small  anguillulidae  with  double  dilatation  of  the  oesophagus  ;  no  teeth 
in  the  oral  cavity  ;  two  short  spicules  provided  with  accessory  pieces  ;  no 
lateral  ridges. 

i.      Rhabditis  pellio  (Schneider),  1866. 
Syn.  :  Pelodera  pellio ,  Serin. ,  1866  ;   Rhabditis  genitalis,  Scheiber,  1880. 

Males,  O'8 — 1*05  mm.  in  length;  females,  0*9 — 1-3  mm.  in 
length.  The  posterior  extremity  of  the  body  of  the  male  has  a 
heart-shaped  bursa,  and  seven  to  ten  ribs  on  each  side  ;  the 
bursa  may,  however,  be  lacking.  The  spicules  measure  0^027 — 
0*033  mm.  in  length,  ,but  are  never  quite  alike.  The  posterior 
extremity  of  the  female  is  long  and  pointed ;  the  vulva  lies 
somewhat  behind  the  middle  of  the  body,  the  'ovary  is  single, 
the  eggs  are  oval,  0*06 — 0*035  mm. 

This  species  was  found  in  Stuhlweissenburg  by  Scheiber  in  the  acid 
urine  (containing  albumen,  pus  and  blood)  of  a  woman  suffering  from 
pyelonephritis,  pneumonia  and  acute  intestinal  catarrh  ;  the  observer  was 
able  to  convince  himself  that  the  Nematodes  which  were  found  during  the 
whole  period  of  the  illness  lived  in  the  vagina,  and  were  evacuated  with 
the  urine. 

Oerley  proved  that  this  species  had  long  been  known  ;  during 
its  larval  stage  it  lives  in  earth-worms  (Anguillula  mucronata,  Grube, 
1849)  ;  in  its  adult  stage  it  lives  in  decomposing  matter  in  the 
soil.  By  introducing  individuals  of  this  species  into  the  vagina 
of  mice,  Oerley  succeeded  in  obtaining  their  settlement  and 
multiplication  (facultative  parasitism).  These  Nematodes  must  like- 
wise by  some  means  have  attained  the  vagina  of  Scheiber's 
patient. 

Two  other  cases  described  by  Baginsky  and  Peiper  probably 
belonged  to  the  same  or  a  nearly-related  species. 

LITERATURE. 

SCHEIBER,     S.     H.      Ein    Fall    von    mikr.     kleinen    Rundwiirmern    im    Urin    einer 

Kranken.       (Virchow's  Arch.,   1880,  Ixxxii.,  p.    161.) 

OERLEY,   L.      Die  Rhabditiden  u.  ihre  medicin.   Bedeutung.      Berlin,    1886. 
BAGINSKY.       Haemoglobinurie    mit    Auftreten    von    Rhabditiden    im    Urin.      (Dtsch. 

med.   Wochenschr.,    1887,   No.    27,   p.   604.) 
PEIPER   AND   WESTPHAL.     Ueber    das  Vorkommen   von   Rhabditiden   im   Harne   bei 

Haematurie.       (Centralbl.   f.   klin.   Med.,    1888,  ix.,   p.    145.) 


276  THE    ANIMAL   PARASITES   OF    MAN 

2.      Rhabditis  niellyi,  Blanchard,   1885. 
Syn.  :  Leptodera  niellyi,  Blanchard,   1885. 

In  1882  Nielly  had  a  cabin  boy,  aged  14  years,  under  obser- 
vation in  Brest.  The  lad  had  never  left  the  neighbourhood  of 
Brest,  and  had  suffered  from  itching  papules  on  the  skin  for  five  or 
six  weeks  ;  in  the  papules  the  observer  found  one  or  several  rhab- 
ditis,  measuring  033  mm.  in  length  by  0*030  mm.  in  breadth. 
Their  cuticle  presented  a  delicate  transverse  striation  ;  the  intestine 
was  the  only  internal  organ  recognisable,  and  it  opened  some- 
what in  front  of  the  posterior  extremity.  Therefore,  it  must  have 
belonged  to  the  rhabditis-like  larva  of  a  Nematode,  the  adult  stage 
of  which  is  unknown. 

The  manner  of  infection  was  established  almost  certainly  by  a  further 
observation  of  Nielly's  ;  at  the  commencement  of  the  illness  small  Nema- 
todes  were  found  in  the  blood  of  the  patient  •  later  on,  however,  they 
disappeared,  neither  were  Nematodes  found  in  the  faeces,  urine  or  sputum. 
Therefore  it  must  be  concluded  that  the  cabin  boy,  who  was  in  the  habit 
of  drinking  water  from  brooksi  had  thus  ingested  embryo-containing  eggs 
of  a  Nematode  ;  the  young  hatched  out  in  the  intestine,  perforated  it, 
reached  the  blood  and  then  settled  in  the  skin.1  -V'' 

It  may  be  remarked  that  skin  diseases  caused  by  young  Nematodes 
have  also  been  observed  in  dogs  (Siedamgrotzky,  Moller,  J.  G.  Schneider-), 
foxes  (Leuckart)  and  horses  (Semmer)  ;  Ziirn  also  found  young  Nematodes 
{Anguillulidce}  in  the  flesh  of  pigs. 

Gen.  2.     AnguilMina,  Gervais  et  Beneden,  1859. 

Syn.:   Tylenchus,  Bastian,   1864. 

Differentiated  from  Rhabditis  by  the  possession  of  a  spine  in  the  oral 
cavity  ;  bursa  without  papillae  in  the  male  ;  uterus  asymmetrical.  Numer- 
ous species  parasitical  in  plants. 

Anguillulina  putrefaciens,  Kiihn,   1879. 
Syn.  :   Tylenchus   putrefaciens,    Kiihn  ;    Trichina   contorta,  Botkin,    1883. 

In  1883  Botkin  (Pet.  kl.  Wochenschr.,  1883)  found  a  small  Nematode, 
which  was,  however,  entirely  misunderstood,  in  the  material  vomited  by  a 
Russian  ;  this  was  not,  however,  a  species  of  Trichinella,  but  an  Anguil- 
lulina living  in  onions  which  had  already,  in  1879,  been  described  by  Kiihn 

1  Nielly,  "  Un  cas  de  dermatose  parasitaire  observ£  pour  la  premiere  fois  en  France  " 
(Arch.  med.  nav.,  1882,  xxxvii.,  pp.  337  and  488).  Bull.  Acad.  med.,  1882  (2)  xi  DO 
395,  S8i). 

'J  Scttneider,  J.  G.,  "  Nematodenembryon.  in  d.  Haut  d.  Hundes.,"  In.-Diss.  Basel 
(Ludwigshof.,  1895). 


STKONGYLOIDES    IXTESTINALIS 


277 


as    Tylenchus  putrefaciens.      These   creatures   attained    the   stomach  with   the 
onions,  causing  nausea  and   vomiting. 

(b)  Fam.  Angiostomida. 

Gen.  3.     Strongyloides,  Grassi,  1879. 
Syn.,  Pseudorhabditis,   Perroncito,  1881  ;  Rhabdonema,  Leuckart,  1882,  p.p. 

The  parasitical  form 
possesses  a  simple  mouth 
without  teeth  and  with- 
out a  spine  ;  the  cylin- 
drical oesophagus  is  very 
long  and  almost  reaches 
to  the  middle  of  the  body. 
The  free-living  form  pos- 
sesses a  small  oral  cavity  ; 
the  oesophagus  is  short, 
exhibits  a  double  dilata- 
tion, in  the  hinder  part  of 
which  there  are  small 
teeth  ;  two  spicules  of  equal 
size. 


Strongyloides   intesti- 
nalis,  Bavay,  1877. 

Syn.  :  Anguillula  intesti- 
nalis  et  stercoralis,  Bavay, 
1877  ;  Leptodera  intestinalis 
et  stercoralis,  Cobb  ;  Pseu- 
dorhabditis  stercoralis,  Per- 
roncito, 1 88 1  ;  Rhabdonema 
Strongyloides,  Leuckart, 
1883  ;  Strongyloides  intes- 
tinalis, Grassi,  1883  ;  Rhab- 
ponema  -intestinale,  Blan- 
chard,  1886. 

In  1876,  a  number  of 
French  soldiers  returned 
to  Toulon  from  Cochin 
China  suffering  from  severe 
diarrhoea.  Dr.  Normand, 
the  doctor  under  whose 

treatment  they  were,  discovered  a  large  number  of  small  Nematodes 
in  the  evacuated  fseces,  and  Bavay  described  them  as  Anguillula  stercoralis. 
Soon  after  Normand,  at  the  post  mortem  of  a  man  who  had  died  of 
Cochin  China  diarrhoea,  found  numerous  other  Nematodes  in  the  intestine, 


FIG.  191. — Strongyloides  intestinalis.  At  the  left 
side  is  a  mature  female  from  the  intestine  of  a 
man  ;  natural  size,  2-5  mm.  Next  to  it  there  is  a 
rhabditis-form  larva  from  freshly  evacuated  faeces 
(i  20/1),  and  a  filariform  larva  from  a  culture  (120/1). 


278  j  THE    ANIMAL    PARASITES    OF    MAN 

and  these  he  likewise  handed  over  to  Bavay.  The  latter  recognised  another 
species,  and  described  it  as  Anguillula  intestinalis .  Both  forms  were  then 
regarded  as  the  cause  of  Cochin  China  diarrhoea,  until,  in  1882,  Leuckart 
was  able  to  demonstrate  that  the  two  forms  are  only  two  succeeding 
generations  of  the  same  species,  of  which  the  one  (A.  intestinalis}  lives 
parasitically  in  the  intestine,  whereas  its  young  (A.  stercoralis)  attain  the 
open,  where  they  come  to  maturity  and  propagate.  The  young  of  these 
live  a*gain  parasitically.  There  thus  exists  the  same  heterogony  as  was 
discovered  by  Leuckart  in  Rhabdonema  nigrovenosum  of  frogs,  which 
heterogony  indeed,  according  to  v.  Linstow,  appertains  to  the  entire  family 
of  the  Angiostomidae* 

(1)  The   parasitical  generation   (Anguillula  intestinalis}   measures 
2*2    mm.    in    length,    and    0*034    mm.    in    breadth  ;     the    cuticle    is 
finely    transversely    striated ;     the    mouth    is    surrounded    by    four 
lips ;     the    oesophagus    is    almost    cylindrical    and    a    quarter    the 
length  of  the  entire  body.     The  anus  opens   shortly  in  front  of  the 
pointed  posterior  extremity  ;    the  female  genital  orifice  is    situated 
in  the    posterior    third    of    the    body ;     the    eggs    measure    0*050 — 
0*058    mm.   in   length,     and    0*030 — 0*034    mm.     in    breadth.      As 
is   the   case   in  Rhabdonema    nigrovenosum,    Leuckart    considers  this 
generation  to  be  .  hermaphroditic  ;    other    authors    (Rovelli)   regard 
it  as  consisting  of  females  reproducing  by   parthenogenesis. 

(2)  The  free-living  generation  (Anguillula  stercoralis)  is  certainly 
sexually  differentiated  ;   its   body  is   smooth,   cylindrical,   somewhat 
more    slender    at    the    anterior   extremity    and    pointed    at    the    tail 
end.     The  mouth  has  four  indistinct  lips  ;    the  oesophagus  is  short, 
with    a    double    (rhabditis-like)    dilatation  ;     there    are    three    little 
teeth  in  the  posterior  dilatation  ;    the  anus  opens  in  front  of  the 
tail   end.      The   males   measure   0*7   mm.   in  length,   0*035   mm-    in 
breadth.      They    carry    their    posterior    end    rolled    up  ;     the    two 
spicules  are  small  and  much  curved.     The  females  measure  I  mm. 
in   length   or   a  little   over ;     0*05   mm.    in   breadth.      The   tail-end 
is    straight    and    pointed ;     the    vulva    lies    somewhat    behind    the 
middle    of    the    body.      The    yellowish,    thin-shelled    ova    measure 
0*07  mm.  in  length,   and  0*045  mm-  in  breadth. 

As  Askanazy  has  shown  the  form  that  lives  parasitically  bores 
deeply  into  the  mucous  membrane  of  the  intestine,  and  frequently 
into  the  epithelium  of  Lieberkiihn's  glands,  both  for  nourishment 
and  oviposition.  The  eggs  then  develop  in  the  intestinal  wall.  The 
young,  which  are  hatched  out,  and  measure  0*2  mm.  in  length,  again 
reach  the  lumen  of  the  intestine,1  and  grow  to  double  or  three  times 

1  As  a  case  published  by  Teissier  testifies,   they  may  also  abnormally  appear  in 
the  circulatory  system  (Arch.  mid.  exp£r.  et  d'an.  path.,  1895,  vii.,  p.  675). 


STRONGYLOIDES    INTESTINALIS 


279 


that  size,  until   they  are'  passed  out  with  the   faeces.      They  already 
differ  from  the   parent    in   the   shape    in   the    oesophagus.      When 
the    external  temperature    is  sufficiently  high    (26   to  35°    C.),  they 
become  mature  after  moulting. 
In  about  thirty  hours  they  are 
completely   developed   and  co- 
pulate.     At    a    low    tempera- 
ture  they  certainly   cast   their 
skin,   but   do  not  escape  from 
the    old    cuticle    and    do    not 
develop    further.      At    a  tem- 
perature of  about  25°  C.   only 
some     of     the     larvae     attain 
maturity. 

Every  female  of  the  free- 
living  generation  deposits  from 
thirty  to  forty  eggs,  which 
develop  rapidly,  sometimes 
even  within  the  uterus.  After 
the  young  have  emerged  from 
the  egg  -  shell,  they  measure 
0*22  mm.  in  length,  and  possess 
the  characteristics  of  the  pa- 
rents (rhabditis  form).  When 
they  have  grown  to  0*55  mm. 
they  moult,  and  while  losing 
their  own  characteristics  they 
acquire  the  characteristics  of 
their  grandparents  (Strongy- 
loid  or  Filariform  larvae).  After 
about  eight  days  the  free-living 
adult  generation  in  the  cul- 
tures has  disappeared,  and  all 
the  young  have  been  trans- 
formed into  the  Strongyloid 
form ;  they  then  die  off  unless 
they  reach  the  intestine. 

This  cycle  of  development  holds  good  for  Strongyloides  intesii- 
nalis  of  tropical  origin  (Bavay,  Leuckart,  Leichtenstern,  Zinn).  In 
the  European  Strongyloides  the  free-living  generation,  as  a  rule, 
is  absent  (Grassi,  Sonsino,  Leichtenstern,  Braun)  ;  the  rhabditis- 
like  larvae  evacuated  with  the  faeces  are  transformed  into  the 


FIG.  iQ2. — Strongyloides  intcstinalis. 
On  the  left  above  a  larva  from  the  faeces  ; 
under  it  a  male  of  the  free-living  genera- 
tion, on  the  right  a  female.  Magnified. 
(After  Zinn.) 


280  THE   ANIMAL   PARASITES    OF   MAN 

Strongyloid  or  Filariform  type  of  larva  in  the  cultures,  which  are 
easily  prepared,  and  in  any  case  will  become  adult  if  introduced 
into  man. 

Occurrence  in  Man. — As  already  mentioned,  Strongyloides  intestinalis  was 
first  observed  in  persons  suffering  from  so-called  Cochin  China  diarrhoea. 
By  the  enormous  numbers  of  parasites  evacuated  with  the  faeces,  the  cause 
of  the  disease  could  be  diagnosed  at  a  glance.  It  appeared,  however,  that 
only  some  of  the  soldiers  returning  from  Cochin  China  and  Martinique, 
and  suffering  from  diarrhoea,  harboured  Strongyloides  (Chauvin).  Breton  made 
the  same  observations  irl  Cochin  China  and  found  that  only  10*4  per  cent,  of 
cases  of  chronic  dysentery,  and  8'8  per  cent,  of  chronic  diarrhoea,  show 
Strongyloides.  Normand,  moreover,  learned  that  only  a  few  of  the  Euro- 
peans residing  in  Cochin  China  are  exempt  from  Strongyloides  intestinalis, 
yet  the  people  exhibit  no  intestinal  symptoms  ;  if,  however,  from  any 
cause  a  catarrhal  condition  of  the  intestine  supervenes  the  condition  is 
changed,  the  parasites  appear  in  larger  numbers,  and  the  disorder  is 
considerably  intensified. 

Strongyloides  intestinalis,  besides  being  present  in  the  Indo-China  region, 
also  occurs  in  the  Antilles,  in  Brazil,  Africa  and  Europe  ;  in  1878  it  was 
discovered  in  Italy  by  Grassi  and  C.  and  E.  Parona  ;  in  1880  it  was  also 
found  in  the  labourers  working  at  the  St.  Gothard  tunnel.  It  was 
imported  into  Germany,  Belgium  and  the  Netherlands  by  Italian  labourers. 
One  sporadic  case  has  been  observed  in  East  Prussia,  and  the  worm  has 
also  been  reported  *  from  Siberia. 

LITERATURE. 

NORMAND,  A.     Sur  la  maladie  dite  diarrhee  de  Cochinchine.     (C.   R.  Ac.   sc.   Paris, 

1876,  Ixxxiii.,  p.  316.) 

Mem.  sur  la  diarrhee  de  Cochinchine.     (Arch.  med.  nav.,  1877,  xxvii.,  p.  35.) 
Du  role  etiologique  de  I'anguillule  dans  la  diarrhee  de  Cochinchine.    '(Ibid-,  1878, 

xxx.,  p.  214.) 
BAVAY.     Sur  I'anguillule  stercorale.     (C.  R.  Asc.  sc.  Paris,  1876,  Ixxxiii.,  p.  694.) 

Sur  I'anguillule  intestinale,  &c.     (Ibid.,  1877,  Ixxxiv.,  p.  266.) 
DOUNON.     Etudes  sur  1'anatomie  pathol.  de  la  dys.  chron.     (Arch,  de  phys.,    1877, 

ix.,  p.  774.) 
CHAUVIN.     L'anguillule  stercorale  dans  la  dysenteric  des  Antilles.     (Arch.  med.  nav., 

1878,  xxix.,  p.  154.) 

GRASSI,   B.     Sovra  1'anguillula  intestinale.     (Rend,    ist   lomb.    sc.    e   lett.,    1879   [2], 

xii.,  p.  228.) 
GRASSI,   B.,   and   C.    PARONA.     Sovra  ranguillula  intestinale,    &c.     (Arch.    sc.    med., 

1879,  in.,  p.  10.) 

PERRONCITO,  E.     Obs.  sur  le  devel.  de  1'anguillula  intestinalis  Bav.     (Journ.  de  1'anat. 

et  de  la  phys.,  1887,  xvii.,  p.  499.) 
LEUCKART,  R.     Ueber  die  Lebensgesch.  d.  sog.  Anguill.  stercor.,  &c.     (Ber.  d.  math.- 

phys.  Cl.  d.  k.  sachs.  Ges.  d.  Wiss.,  1883,  p.  85). 
SEIFERT.     Ueber  Anguill.  stercoralis.     (Stzgsb.   d.  phys.-med.  Ges.    Wiirzburg,    1883, 

p.  22.) 
GRASSI,  B.,  and  R.  SEGRE.     Nuove  osservaz.  sull'  eterogenia  del  Rhabd.  intest.     (Atti 

R.  Accad.  Lincei.  Rendic.,  1887  [4],  iii.,  p.  100.) 
ROVELLI,  G.     Rich.  s.  org.  genit.  d.  Strongyloides.     Como,  1888.. 
SONSINO,  P.     Tre  casi  d.  mal.  da  Rhabd.  intest.  o  Rhabdonemiasi.     (Suppl.  d.  Riv. 

gen.  ital.  di  clin.  med.,  1891,  20,  vii.) 
LEICHTENSTERN,   O.     Ueb.   Anguillula  intest.     (Dtsch.   med.  Wchschr.,    1898,   No.   8, 

p.  118.) 
Z.  Lebensgesch.  d.  Ang.  intest,     (C.  f.  B.,  P.  u.  I.,  1899  [i],  xxv.,  p.  226.) 


GNATHOSTOMA    SIAMENSE 


28l 


PAPPENHEIM.     Ein  sporad.  Fall  v.  Ang.  int.  in.  Ostpreuss.     (Ib.,  1899,  xxvi.,  p.  608.) 

BRAUN,  M.     Bemerk.  z.  d.  spor.  Fall  v.  Ang.  int.  in  Ostpr.     (Ib.,  p.  612.) 

ZINN,  W.     Ueb.  Ang.  intest.     (Ib.,  p.  626.) 

ASKANAZY,  M.     Ueb.   Art.   u.   Zweck  d.   Invas.   d.  Ang.  int.  i.   d.   Darmwand.     (Ib., 

1900,  xxvii.,  p.  569.) 
KURLOW,  M.  von.     Ang.  int.  als  Urs.  blut.  Durchf.  b.  Mensch.     (C.  f.  B.,  P.  u.  I., 

1902  [I],  xxxi.,  Orig.,  p.  614.) 


(c)  Fam.  GnathostomidcB. 

Gen.  4.     Gnathostoma,  Owen,  1836. 

Syn.  :  Cheiracanthus,  Diesing,   1839. 

Easily  recognisable  by  the  numerous  spines  which  cover  the  entire  body  or 
only  the  anterior  extremity,  and  terminate  in  several  points  ;  head  globular 
and  beset  with  bristles  ;  mouth  with  two  lips  ;  two  spicules  ;  vulva  situated 
behind  the  middle  of  the  body. 

Gnathostoma  siamense,  Levins.,  1889. 
Syn.  :  Cheiracanthus  siamensis,  Lev.,   1889. 

Only  one  specimen,  a  female,  has  hitherto  been  known  ;  it 
measures  9  mm.  in  length,  I  mm.  in  breadth.  '  There  are  eight 
rows  of  bristles  around  the  head  ; 
the  armature  of  spines  extends 
over  the  anterior  third  of  the  body 
only  ;  each  spine  on  the  anterior 
region  of  the  body  spreads  into 
three  points,  of  which  the  middle 
one  is  the  longest  ;  the  posterior 
spines  are  simple  ;  they  gradually 
become  smaller,  and  then  disappear 
entirely.  The  vulva  is  situated 
behind  the  middle  of  the  body. 

The  single  specimen  described  by 
Levinsen  was  found  by  Dr.  Deuntzer  in 
Bangkok  (Siam)  and  was  obtained  from 
a  young  Siamese  woman  who  suffered 
from  a  small  tumour  of  the  breast,  which 
had  developed  in  the  course  of  a  few  T  F\G'  ?93-  —  Gnathostoma  siamense. 

To  the  left,  the  entire  worm,  8/1  ;  to 
days.       After   the    disappearance  of    the    the  right  the  head  seen   from  above, 

tumour,  nodules,  the  size  of  beans,  were    about  40/1.     (After  Levinsen.) 

found  in  the  skin  ;    out  of   one  of   these 

the  worm  was  obtained.     The  same  doctor  observed  this  affection  in  two  other 

persons.1 

'Levinsen,  G.  M.  R.,  "  Om  en  ny  rundworm  hos  mennesket"  (Vidensk.  meddel. 
fra  naturh.  Foren.  i.  Kjobenhavn  /.,  1889,  p.  323,  with  one  plate).  Ref.  in  Centralbl.  /. 
Bad.  u.  Paras.,  1890,  viii.,  p.  182. 


282  THE   ANIMAL    PARASITES    OF   MAN 

A  closely  related  species,  Gn.  spinigerum,  Ow.,  lives  in  the  stomach  of 
some  species  of  wild  cats  (Felis  catus,  F.  concolor,  F,  tigris}  ;  another  species 
(Gn.  hispidiim,  Fedsch.)  lives  in  the  stomach  of  pigs  in  Turkestan,  but  has 
also  been  found  by  Csoker  in  pigs  in  Hungary,  and  by  Collin  in  the 
stomach  of  an  ox  (Berlin).  The  pariah  dogs  of  Calcutta  are  also  subject 
to  a  species  of  Gnathostoma. 


(d)  Fam.  Filariidce. 
Gen.  5.     Filaria,  O.  Fr.  Miiller,  1787. 

These  are  mostly  very  long,  slender  Nematodes,  the  males  of  which  are 
usually  considerably  smaller  than  the  females.  The  tails  of  the  males  are 
bent  or  spirally  rolled,  and  sometimes  bear  little  wing-like  appendices. 
The  two  spicules  are  very  unlike  in  size  and  structure  ;  almost  always  there 
are  four  pre-anal  papillae,  but  the  number  of  post-anal  papillae  varies.  The 
vulva  is  always  situated  at  the  anterior  extremity.  The  nlariae  live  para- 
sitically  chiefly  in  the  serous  cavities  and  in  the  subcutaneous  connective 
tissue. 

i.    Filaria  medinensis,  Velsch,  1674. 

Syn.  :  Vena  medinensis,  Velsch,  1674  ;  Dracunculus  Persarum,  Kampfer, 
1694;  Gordius  medinensis,  Linne,  1758;  Filaria  dracunculus,  Bremser,  1819  ; 
Filaria  cethiopica,  Valenciennes.,1  ^1856  ;  Dracunculus  medinensis,  Cobbold, 
1864  ;  Guinea  worm,  Medina  worm. 

The  females  attain  a  length  of  50 — 80  cm.,  or  even  more,  and 
average  0^5 — 1-7  mm.  in  diameter.  They  are  whitish  or  yellowish 
in  colour.  The  anterior  extremity  is  roundish.  The  mouth  opening 
is  surrounded  by  two  lips,  behind  which  there  are  two  lateral  and 
four  sub-median  papillae  ;  the  posterior  end  terminates  in  a  spine, 
ventrally  directed,  and  about  i  mm.  in  length  ;  the  alimentary  canal 
below  the  oesophagus  is  atrophied,  but  not  entirely  obliterated  ;  the 
lateral  ridges  are  very  flat.  The  greater  part  of  the  body  is  occupied 
by  the  long  uterus,  in  which  a  great  number  of  young  larvae  are 
always  found.  The  ovaries  probably  lie  at  the  ends  of  the  uterus  ; 
the  vulva  and  vagina  are  not  known. 

According  to  a  recent  observation  of  R.  H.  Charles,  the  male 
of  Filaria  medinensis  has  at  last  been  discovered.  On  two 
female  filariae,  which  were  found  in  a  post  mortem  at  Lahore,  a 
smaller  worm,  measuring  about  4  cm.,  was  found  clinging  to  each, 
attached  by  its  posterior  extremity  to  a  part  of  the  female  about 
14  cm.  from  the  head  extremity.  It  may  be  assumed  that  the 
males  were  attached  to  the  vulva  of  the  females,  as  is  the  case 


FILARIA    MEDINENSIS 


in  Syngamus  trachealis,1 
and  that  the  males  die 
after  copulation. 

Occurrence. — Filaria  me- 
dinensis  has  been  known 
since  the  most  remote 
period.  The  "  fiery  ser- 
pents "  that  molested  the 
Israelites  by  the  Red  Sea, 
and  which  Moses  men- 
tioned, were  probably 
filariae.  The  term  &.pa.K6vTtoi> 
already  occurs  in  Aga- 
tharchides  (140  B.C.). 

Galen  called  the  disorder  dracontiasis  ;  the  Arabian 
authors  were  well  acquainted  with  the  worm.  It 
is  found  not  only  in  Medina  or  Arabia,  but  also 
in  Persia,  Turkestan,  Hindostan.  The  Medina  worm 
is  also  widely  distributed  in  Africa,  on  the  coasts 
as  well  as  in  the  interior.  (The  English  term  is 
Guinea  worm.-)  It  was  carried  to  South  America 
by  negro  slaves,  but  is  said  to  have  again  dis- 
appeared thence  ;  it  is  also  frequently  observed  in 
mammals  (ox,  horse,  dog,  leopard,  jackal,  Canis 
lupaster,  &c  ). 


FIG.  194  (a). — Anterior 
extremity  of  Guinea  worm. 
Alter  Leuckart. 


FIG.  194  (&). — Transverse  section  of  female  Guinea 
worm  ;  u.,  uterus  containing  embryos  ;  i.,  intestinal 
canal  ;  o.,  ovary.  After  Leuckart. 


FIG.  194.  — Guinea 
worm  (Filaria  medi- 
nensis).  After  Leuck- 
art. 


1  The  confirmation  of  this  opinion  can  be  seen  in  an  observation  of  Neumann, 
who,  in  the  connective  tissue  of  Python  natalensis,  found  the  males  as  well  as  the  con- 
siderably larger  females  of  Filaria  dahomensis  ;  the  males,  apparently  after  copulation, 
finally  die  off  and  become  calcified  (Bull.  soc.  zool.,  France,  1895,  xx.,  p.  123). 


284  THE   ANIMAL    PARASITES    OF    MAN 

Filaria  medinensis  in  its  adult  stage  lives  beneath  the  surface 
of  the  body  ;  it  is  seen  most  frequently  on  the  lower  extremities, 
more  especially  in  the  region  of  the  ankle  ;  but  it  also  occurs  in 
other  parts  of  the  body — on  the  trunk,  scrotum,  perinseum,  on  the 
upper  extremities,  and  in  the  eyelids  and  tongue.  As  a  rule, 
there  is  only  one  ulcer  and  one  worm,  rarely  several.  It  attacks 
man  without  distinction  of  race,  age  or  sex.  It  is  observed  most 
frequently  during  the  months  of  June  to  August. 

The  following  is  known  of  the  development  of  this  filaria  :  The  larvae, 
which  in  form  resemble  those  of  Cucullanus-  belonging  to  the  order  of 
the  Nematoda,  can  only  reach  the  open  after  the  bursting  of  the  mother's 
body.  For  a  few  days  they  live  in  water  or  moist  soil,  and  can  with- 
stand desiccation  for  a  few  hours.  In  consequence  of  their  similarity 
to  those  of  Cucullanus  elegans  (parasite  of  Perca  fluviatilis\  which  live  in 
Cyclops,  Fedschenko,  by  the  advice  of  Leuckart,  introduced  the  larvae  of 
the  filaria  into  water  containing  cyclops,  the  larvae  of  insects,  &c.,  and 
was  able  to  confirm  their  invasion  of  the  cyclops  (not  per  os)  but  through 
the  integuments  of  the  body).  On  about  the  twelfth  day  they  cast  their 
skin  and  assumed-  another  form.  They  could  be  observed  within  the 
cyclops  until  the  fourth  week,  yet  no  changes  occurred  though  the  larvae 
grew  to  a  length  of  i  mm.  The  experiment  to  infect  young  cats  and 
dogs  with  filariae  by  giving  them  infected  cyclops  in  milk  or  water  failed. 
There  is,  however,  always  the  possibility  that  the  infection  of  man  is 
accomplished  in  this  manner.  A  series  of  observations  appear  to  demon- 
strate that  the  period  of  incubation  averages  from  eight  to  ten  months. 

P.  Manson  and  R.  Blanchard  have  recently  repeated  the  infec- 
tion experiments  with  fresh-water  cyclops,  and  have  convinced  them- 
selves of  the  correctness  of  Fedschenko's  observations.  Daphnidae 
were  not  used,  only  Copepodse  (Cyclops  strenuus,  C.  bicuspidatus, 
and  C.  viridis).  As  the  species  mentioned  are  indigenous  forms, 
Blanchard  thinks  the  probability  is  not  excluded  that  the  Medina 
worm  if  imported — and  such  importation  does  occur — may  also 
settle  in  Europe. 

LITERATURE. 

BASTIAN,  A.     On  the  Structure  and  Nature  of  the  Dracunculus.     (Transact.   Linn. 

Soc.,  1863,  xxiv.,  p.  101.) 

LEUCKART,  R.     Die  menschlichen  Parasiten,  &c.     (1876,  i.,  Edit,  ii.,  p.  644.) 
FEDSCHENKO.     Bau  und  Entwickelung  der  Filaria.     (Ber.   d.   K.   Ges.   der  Frde.   d. 

Natur.  Anthrop.  u.  Ethnogr.,   1879,  viii.  [i],  p.  71,  i  plate,  Russ.) 
MOSLER,  F.     Ueber  die  medic.  Bedeutung  des  Medinawurmes.     Wien,  Lpzg.,  1885. 
CHARLES,  R.  TL     History  of  the  Male  Fil.  med.     (Scientif.  Mem.  Med.  Omc.  Army 

of  India,  vii.,  1892,  Calcutta.) 
RAILLIET,  A.     De  1'occurence  de  la  Filaire  de  Medine  chez  les  animaux.     (Bull.  soc. 

zool.  de  France,  1889,  xiv.,  p.  73.) 

BLANCHARD,  R.     Mai.  par.,  par.  anim.,  Paris,  1895,  p.  768. 
MANSON,  P.     On  the  Guinea-worm.     (Brit.  Med.  journ.,  London,   1895,  ii.,  p.   1350; 

The  Lancet,  1895,  xxxvii.,  ii.,  p.  309.) 


FILARIA    IMMITIS  285 

2.     Filaria  immitis,  Leidy,   1856. 

The  body  is  very  thin  and  filiform  ;  the  posterior  extremity 
is  pointed,  and  the  anterior  one  rounded  off ;  the  mouth  is 
terminal,  and  behind  it  there  are  six  small  papillae  ;  the  anus  opens 
near  the  posterior  extremity  ;  the  male  measures  12 — 18  cm.  in 
length,  0*7 — O'Q  mm.  in  breadth  ;  the  tail  is  slender  and  twisted 
like  -a  cork-screw  ;  it  has  a  fold  of  skin  at  either  side  and  four 
pairs  of  large  pre-anal,  and  some  smaller  post-anal  papillae,  the 
surface  of  which  exhibit  a  smooth  appearance.  The  female 
measures  25 — 30  cm.  in  length  and  ro — 1-3  mm.  in  breadth ; 
the  vulva  is  about  7  mm.  distant  from  the  anterior  extremity  ; 
viviparous  ;  the  larvae  measure  0^285 — 0*295  mm.  in  length,  and 
0-005  mm.  in  breadth  ;.  the  posterior  extremity  terminates  in  a 
very  thin  point. 

Filaria  immitis  lives  chiefly  in  the  right  cavities  of  the  heart,  also  in  the 
venous  system  of  dogs,  but  appears  also  to  occur  in  the  wolf  (Japan)  and 
in  the  fox  ;  in  Europe  it  is  most  frequent  in  Italy  ;  it  is  very  frequent  in 
China  and  Japan,  where,  according  to  Janson,  about  50  per  cent,  of  the 
dogs  are  infected.  It  has  also  been  observed  in  N.  and  S.  America. 

According  to  Bowlby,  this  species  occurs  also  in  man.  At  the 
post  mortem  of  an  Arab,  who  had  suffered  from  'haematuria,  this 
author  found  numerous  filariae  in  the  portal  vein,  and  the  eggs 
of  Nematodes  in  the  thickened  wall  of  the  bladder,  in  the  kidneys, 
ureters,  and  in  the  lung.  Similar  eggs  are  also  said  to  have  been 
found  in  a  rectal  tumour  in  a  youth,  aged  17.  The  filariae  found 
were  identified  as  Filaria  immitis, 

[The  eggs  of  Nematodes  found  by  Bowlby  in  the  thickened  wall 
of  the  bladder,  in  the  kidneys,  ureters  and  in  the  lung  of  an 
Arab  suffering  from  haematuria,  were  undoubtedly  those  of 
Schistosoma  hcematobium.  Probably  the  worms  he  found  in  the 
portal  vein  of  the  same  patient  were  female  specimens  of  Schistosoma 
and  not  specimens  of  Filaria  immitis. — L.  W.  S.] 

Large  numbers  of  Nematodes  of  a  considerable  length  were  found  in  the 
veins  of  a  Russian  whose  body  was  dissected  in  Dorpat  in  1885.  Having 
myself  seen  and  prepared  the  well-preserved  worms  I  could  not  fail  to 
observe  their  filarial  nature,  but  I  am  not  in  a  position  to  give  more 
details  as  I  was  unable  to  examine  them  more  minutely. 

The  life  history  of  Filaria  immitis  has  been  elucidated  by 
Grassi  and  Noe.  It  was,  however,  already  known  that  the  larvae 
appear  in  the  blood  of  infected  dogs,  especially  during  night  time. 

The  larvae  of  Filaria  immitis,  like  the  malaria  parasites,  are  taken 


286 


THE   ANIMAL    PARASITES    OF    MAN 


up  with  the  bloo'd  by  mosquitoes  in  the  process  of  sucking  ;    how- 
ever,   whilst    for    the    malaria    parasites    of     man    only    the    genus 

Anopheles  comes  into  consideration,  the  larvae 
of  Filaria  immitis  thrive  equally  well  in 
Anopheles  and  Culex.  The  conditions,  how- 
ever, are  not  quite  alike,  because  Cule% 
pipiens  is  not  so  easily  infected.  The 
filarial  larvae,  however,  leave  the  stomach 
of  the  mosquito,  and  penetrate  into  the 
malpighian  tubes  or  their  epithelial  cells. 
They  here  undergo  a  series  of  changes, 
moult,  and  on  the  twelfth  day  after  the 
infection  of  the  mosquitoes  perforate  the 
organ  they  have  been  inhabiting,  and  thus 
reach  the  body  cavity,  which  communicates 
with  the  labium  ;  by  penetrating  into  the 
thorax,  the  larvae,  which  have  attained  a 
length  of  O'9  mm.,  reach  the  head  and 
finally  the  labium,  where  they  await  until 
the  mosquito  bites  a  dog.  Though  the, 
labium  is  not  introduced  into  the  wound 
made  in  biting,  but  bends  backwards,  forming 
an  angle,  yet  during  the  process  it  tears  its 
very  delicate  cuticle,  and  the  larvae  avail 
themselves  of  this  rent  to  escape.  They 
penetrate  between  the  labium  and  the  sty- 
lets, thus  finding  the  wound,  which  enables 
them  to  enter  into  the  vascular  system.  In 
order  to  meet  the  objection  that  the  dogs 
infect  themselves  per  os — that  is  to  say,  by 
biting  and  swallowing  infected  mosquitoes 
swarming  around  them,  the  experimental 
animals  were  prevented  (by  muzzles)  from 
devouring  the  mosquitoes.  These  experi- 
ments also  succeeded. 

[Grassi  and  Noe's  theory  as  to  the  mode 
of  escape  of  Filaria  immitis  is  untenable. 
The  filariae  escaping  through  a  rent  of  the 
labium  at  the  part  which  bends  during  suc- 
tion would  be  unable  to  reach  and  penetrate 
the  wound  made  by  the  lancets.  In  a  paper 
published  in  the  Journal  of  Tropical  Medicine^  Dr.  Button  suggested 


.    \ 

FIG.  195.  —  Filaria 
immitis,  natural  size  ;  the 
male  is  on  the  left  and 
the  female  on  the  right 
side.  (After  Railliet.) 


'August  I5th,  1901. 


FILARIA     IMMITIS 


287 


that  the  filariae  might  possibly  escape  at  the  tip  of  the  labium  between 

the  labellae.     In  a  second  and  more  recent  paper1  on  the  Transmission 

of  F.  immitis,  Dr".  Noe  admits  that  it  is  impossible  for  the  filariae  to 

escape,  as  he  had  at  first  suggested.      Having  made  numerous  and 

suitable  experiments  he  found  that  the  filariae  invariably  died  when 

extruded  at   the  seat  of  the  bend.     He 

therefore  believes  that  the   filariae  must 

leave  their  insect  host,    as  suggested   by 

Button,  through  the   delicate  structures 

between   the  labellae   at    the   tip   of   the 

labium. 

Having  noticed  that  the  filariae  (both 
F.  immitis  and  F.  bancrofti)  collect  in 
the  lacunoma  round  the  pharynx  or 
pumping  organ  of  the  mosquito,  and 
having  found  them  also  actually  within 
the  pharynx,  I  suggested2  that  they 
might  pierce  the  delicate  membrane 
which  connects  the  chitinous  plates  of 
the  pharynx,  and  thus  reach  the  buccal 
cavity  of  the  insect,  to  pass  between  the 
piercing  organs  into  the  definitive  host. 
I  believe  too  much  importance  has  been  FlG  196._The  inferior  end 
given  to  the  fact  that  the  filariae  are  of  the  mouth  organs  of  a  mos- 

f  ,!          r  i  .,!•          ,,          n    ,.  quito  being  introduced  into  the 

frequently     found     within     the     labium.     ^n  of  a  dog>  by  which  means 

a  filaria,  lying  between  the 
labium  and  the  stylets,  is 
transmitted  to  the  animal. 


Magnified.     (After  Noe.) 


Their   presence  in  the  labium  does   not 

. 

necessarily  mean  that  they  must  escape 
through  that  organ.  It  is  obvious  that 
when  a  number  of  filariae  have  gathered 

round  the  pharynx,  a  few  must  be  pushed  forwards  by  new-comers 
into  those  parts  which  continue  the  body  cavity  anteriorly.  Con- 
sequently the  presence  of  filariae  in  the  labium  has  no  other  signifi- 
cance than  their  not  uncommon  presence  within  the  palpi,  from 
which  they  can  certainty  find  no  means  of  escape.  —  L.  W.  S.] 

Filaria    recondita    is    another    parasite    of    dogs,    the    larv;e    of 
which  appear  in  the  blood;  fleas  are  their  intermediary  hosts. 

LITERATURE. 

BOWLBY.     Two  cases  of  Filaria  immitis  in  Man.     (The  Lancet,  1889,  i.,  p.  786.) 
MAGELHAES,   P.     S.    de.      Die    Filaria  Bancrofti,    Cobb.,   u.     Filaria    immitis,    Leid. 

(C.   f.   B.   u.   P.,    1892,  xii.,  p.    511.) 
GRASSI,    B.      Beitr.    z.    Kenntn.    d.    Entwickelungscyclus   von    5    Paras,    d.^  Hundes 

(Ibid.,  1888,  iv.,  p.  609.) 

'Noe,  G.,   "  Ulteriori  studi  sulla  Filaria  immitis"  (Rend.  Ace.  d.  Lincei,   vol.   xii., 
1903). 

-Sambon,  L.  W,,  "  Fi!aria  Bancrofti  and  Filaria  immitis"   (Lancet,  1902.) 


288  THE    ANIMAL    PARASITES    OF    MAN 

GRASSI,  B.,  and  CALANDRUCCIO.     Ueber  Hacmatozoon,  Lewis.     (Ibid.,  1890,  vii.,  p.  18. 
LEWIS,   T.   R.     On    Nematode  Haematozoa  in   the  Dog.     (Quart.    Journ.   Micr.   Sc., 

1875,   xv.,  p.   268.) 
SONSINO,    P.      Ricerche    sugli    hemtozoi    del    cane.       (Atti    soc.    tosc.    di    sc.    iiat., 

1888,  x.) 
GRASSI,   B.,   and   G.   NOK.     Uebertrag.   d.    Blutfil.   ganz  ausschliessl.  durch  d.    Stich 

von  Stechmiicken.       (C.   f.   B.,   P.   u.   I.,    1900,   [i.]  xxviii.,   p.   652.) 
Sul    ciclo    evolut.    d.    Fil.    Bancrofti    e.    d.  Fil.    immitis.       (Ric.    Lab.    di    An. 

norm.   R.  Univ.   Roma  ed  in  altri  Labor,   biol.,    1901,  viii.,  p.   275.) 


3.  Filaria  bancrofti,  Cobbold,   1877. 

Syn.  :  Trichina  cystica,  Salisbury,  1868  (nee  Filaria  cystica,  Rud.  1819); 
Filaria  sanguinis  hominis,  Lewis,  1872;  Filaria  sanguinis  hominis  cegyptiaca, 
Sonsino,  1875  ;  Filaria  wuchereri,  da  Silva  Lima;  Filaria  sanguinis  hominum, 
Hall,  1885  ;  Filaria  sanguinis  hominis  nocturna,  Manson  1891  ;  Filaria  nocturna, 
Manson,  1891. 

The  male  is  colourless,  and  measures  about  40  mm.  in  length 
and  O'l  mm.  in  diameter.  The  cephalic  extremity  is  a  little  thick- 
ened, the  posterior  extremity  is  bent  and  rounded,  but  is  not 
twisted  corkscrew-like.  The  anal  orifice  opens  0*138  mm.  in  front 
of  the  posterior  border.  There  are  three  pairs  of  small  pre-anal 
and  an  equal  number  of  post-anal  papillae  ;  the  spicules  are 
unequal  (o-2  and  O'6  mm.  in  length).  The  female  is  brownish, 
76 — 80  mm.  in  length,  0*21 — 0^28  mm.  in  breadth  ;  the  cephalic 
and  caudal  extremities  rounded  ;  the  vulva  is  1*27  mm.  distant 
from  the.  head,  and  the  anus  0*28  mm.  away  from  the  posterior 
extremity.  Almost  the  entire  body  is  occupied  by  the  two  uteri,  from 
which  the  larvce  emerge  early.  The  length  of  the  latter  averages 
0*13 — 0'3  mm.,  their  breadth  0*007 — cron  mm.  They  are  sur- 
rounded by  a  delicate  protective  investing  membrane,  which  is 
not  quite  close  to  them. 

These  parasites  of  man  were  for  a  long  time  only  known  in  their  larval 
stage.  They  were  discovered  in  1863  in  Paris  by  Demarquay,  in  the 
hydrocele  fluid  of  a  Havannese  emptied  by  puncture  ;  they  were  next 
observed  by  Wiicherer,  in  Bahia,  in  the  urine  of  twenty-eight  cases  of 
tropical  chyluria  ;  they  were  likewise  observed  in  North  America  by  Salis- 
bury, who  gave  them  the  name  of  Trichina  cystica.  The  next  discoveries 
in  Calcutta,  Guadeloupe,  and  Port  Natal  related  to  chyluria  patients,  until 
Lewis  discovered  the  larvae  in  the  BLOOD  of  man  (India),"  and  found  they 
were  almost  always  present  in  persons  suffering  from  chyluria,  ELE- 
PHANTIASIS, and  lymphatic  enlargements  ;  he  also,  in  exceptional  cases, 
found  them  in  apparently  healthy  persons  (Filaria  sanguinis  hominis]. 
Lewis  and  Manson  studied  the  disease  and  the  filariae  of  the  blood  very 
minutely,  and  became  aware  that  the  filariae  were  sucked  up  by  mosqui- 
toes with  the  blood.  Manson  described  the  metamorphoses  that  take 
place  within  the  body  of  the  mosquito.  The  adult  female  was  discovered 


FILARIA    BANCROFTI  289 

in  Queensland  by  Bancroft,  and  soon  after  Lewis  found  it  in  Calcutta  ; 
it  was  described  by  Cobbold  as  Filaria  bancrofti.  The  male  was  first  seen 
by  Bourne  in  1888. 

The  lymphatic  vessels  of  various  parts  of  the  body  of  man 
are  doubtless  the  normal  habitat  of  the  ADULT  WORMS,  but  these 
have  also  been  found  in  the  left  ventricle  of  the  heart.  The 
females  are  viviparous,  but  exceptionally  they  also  deposit  eggs  ; 
the  young  larvae,  by  means  of  the  lymph  stream,  reach  the  blood, 
and  are  distributed  with  it  throughout  the  body  ;  they  also  pass 
through  the  blood  vessels,  and  may  be  found  in  the  secretions  of 
glands,  such  as  the  lachrymal  and  Meibom's  glands,  kidneys,  &c. 
The  manner  of  appearance  in  the  peripheral  circulation,  which 
has  been  particularly  studied  by  Manson,  is  peculiar  :  the  larvae 
are  first  seen  in  patients,  the  blood  specimens  of  which  have  been 
taken  after  sunset.  Their  number  then  increases  considerably  until 
about  midnight,  and  after  begins  to  diminish  ;  from  midday  until  the 
evening  no  filariae  are  found  in  the  peripheral  b)ood.  The  cause 
of  this  peculiarity  cannot  be  explained,  as  was  conjectured,  by  a 
periodical  production  of  larvae,  because  the  cycle  can  be  reversed. 
If  the  patients  are  made  to  sleep  in  the  day-time  and  remain 
awake  at  night,  the  filariae  appear  in  the  day-time  and  disappear 
at  night.  The  manner  of  appearance,  therefore,  is  connected  with 
sleep,  and  depends  on  the  fact  (v.  Linstow)  that  during  sleep  the 
peripheral  cutaneous  vessels  are  somewhat  dilated,  but  during  the 
waking  hours  are  contracted  ;  the  filariae  cannot  pass  through  the 
contracted  capillary  system,  but  remain  in  the  larger  trunks  in 
the  depth  of  the  cutis.1 

[The  night  swarming  of  the  larvae  of  F.  bancrofti  in  the  peripheral 
circulation  is  correlated  with  the  life-habits  of  its  liberating  agent. 
We  can  find  a  large  number  of  similar  remarkable  correlations  in 
Nature.  Many  flowers  which  open  early  in  the  morning  are  only 
visited  by  particular  butterflies  which  leave  their  nocturnal  haunts 
at  the  same  hour  ;  other  flowers  do  not  open  till  sunset,  and  they 
are  visited  by  hawk-moths,  silk-moths,  owlet-moths  and  other 
Noctuse,  which  commence  their  ramblings  when  dusk  sets  in. 

Then  again,  the  development  of  flower  scent  is  simultaneous  with 


1  Manson  was  able  to  examine  the  body  of  a  man  who  died  from  poisoning  at 
8.30  a.m.  During  life  the  filariae  had  appeared  regularly  in  the  blood  from  6  p.m.  to 
8  a.m.  They  were  entirely  absent  from  the  peripheral  circulation,  but  were  found 
in  the  large  vessels,  particularly  in  the  arteries ;  further,  in  the  capillaries  of  the  brain 
and  of  the  voluntary  muscles,  in  the  vessels  of  the  kidneys  and  the  heart.  The  largest 
numbers  were  present  in  the  pulmonary  vessels.  Manson  does  not  accept  v.  Linstow's 
explanation,  but  is  of  opinion  that  the  products  of  metabolism  of  a  waking  person 
drives  the  filariae  from  the  periphery  or  attracts  them  to  the  interior  (Manson,  P., 
"  On  Filarial  Periodicity,"  Brit.  Med.  Journ.,  London,  1899,  ii.,  p.  644). 

19 


290 


THE    ANIMAL    PARASITES    OF    MAN 


the  time  of  flying  of  certain  insects.  The  flowers  of  Hesperis  tristis, 
and  other  flowers  which  are  visited  by  small  nocturnal  moths,  give 
off  no  scent  during  the  day,  but  exhale  a  strong  hyacinth  odour  at 
twilight ;  on  the  other  hand,  many  flowers  visited  during  the  day 
become  scentless' at  night. — L.  W.  S.] 

It  is  an  interesting  fact  that  the  appearance  of  the  filariae  in 
the  peripheral  circulation  tallies  with  the  swarming  period  of  the 
mosquitoes,  and  this  affords  the  mosquitoes  the  opportunity  ot 
extracting  some  of  the  filariae  from  the  body  of  human  beings 
whilst  sucking  their  blood  ;  others,  again,  through  the  blood  vessels 

of  the  glomeruli,  attain  the 
urinary  tubules  and  escape  with 
the  urine.  This,  however,  only 
appears  to  be  an  unusual  way. 

The  filariae  appear  in  the  blood 
in  great  numbers — 140,000  ac- 
cording to  Lewis's  calculations,  as 
many  as  30,000,000 — 40,000,000 
according  to  Carter  and  Mac- 
kenzie, provided,  however,  al- 
ways that  their  number  in  the 
total  quantity  of  blood  is  evenly 
distributed  and  equal  to  the 
average  contained  in  the  blood 
tests. 

By  observing  in  the  moist  cham- 

FIG.    197. — Larvae    of    the  Filana  ban- 
crofti  in   the  blood  of    Man.       Magnified,      ber    a     drop    of    blood    containing 

(After  Raiiiiet.)  filarial  larva,  it  will  be  seen  that 

after  a  little  time,  namely,  when 

the  haemoglobin  from  the  blood  corpuscles  appears  in  the  plasma, 
the  filariae  escape  from  their  sheaths  ;  a  six-lipped  collar  is  then 
distinguishable  at  their  anterior  extremity,  surrounding  a  conical  and 
fairly  thick  rostellum,  at  the  point  of  which  there  is  a  retractile 
filament.  This  complicated  structure  appears  to  be  especially  adapted 
for  boring  through  and  dilating  the  tissues.  It  comes  into  action 
when  the  filariae  have  reached  the  intestine  of  mosquitoes,1  where 
the  above-mentioned  alterations  of  the  blood  take  place.  The 
filariae,  which  have  escaped  from  their  sheaths,  bore  through  the 
intestinal  wall  and  settle  amongst  the  thoracic  muscles  of  the 


1  The  species  in  question  are  stated  to  be  Culex  ciliaris,  L.  ;  Culex  skusi,  Giles  ;  Culex 
taniatus,  Meig.  ;  and  Culex  fatigans,  Wied. 

[C.  ciliaris.  L.  =  C.  pipiens,  L. ;    C.  skusi,  Giles  =  C.  fatigans,  Wied.  ;   C.  taeniatus, 
Meig,  =  Stegomyia  fasciata,  Fabr.— F.V.T.]. 


FILARIA   BANCROFTI 

mosquitoes,  where,  in  a  few  days,  as  already  described  by  Mansori 
in  1884,  they  undergo  considerable  changes ;  they  grow  to  a 
length  of  i'5  mm.  and  a  breadth  of  0-25  mm.  Of  course  many 
specimens  perish  within  the  intestine  of  the  mosquito.  The 
general  opinion  was  that  the  filarial  larvae,  after  such  changes, 
attained  the  water  at  the  death  of  the  female  mosquito  and  were 
introduced  into  man  with  the  infected  water.  This  opinion  was 
supported  by  the  observation  that,  whereas  the  unaltered  filarice 
are  exceedingly  susceptible  to  water,  those  that  have  come  to 
maturity  within  the  mosquitoes  can  bear  immersion  very  well. 
Nevertheless,  this  view  is  not  correct,  although  recently  Maitland 
has  sought  to  revive  it.  It  is  more  probable  that  the  larvae  of 
Filaria  bancrofti  are  transmitted  by  the  bite  of  infected  mosqui- 
toes just  like  those  of  Filaria  immitis.  It  is  quite  certain  that 
in  the  last  stage  of  their  metamorphosis  the  larvae  leave  the 
thoracic  muscles  of  the  mosquitoes  and  enter  the  body  cavity  ; 
from  here  they  do  not  reach  the  open  by  way  of  the  oesophagus, 
but  proceed  to  the  mouth  parts,  or  rather  the  labium.  We  may 
therefore  conclude  quite  positively  that  when  the  infected  mosqui- 
toes bite,  the  same  mechanism  that  directs  Filaria  immitis  into 
the  punctured  wound  of  the  dogs  is  likewise  adopted  in  the 
transmission  of  Filaria  bancrofti  to  man.  [The  transmission  of 
Filaria  bancrofti  through  the  mouth  parts  of  mosquitoes  was  sug- 
gested by  me1  and  demonstrated  by  Dr.  G.  C.  Low2  before  Noe  and 
Grassi  published  their  paper  on  the  transmissions  of  Filaria  immit's. 
-L.  W.  S.] 

Filaria  bancrofti,  or  Fit.  sanguinis  hominis,  is  known  in  nearly 
all  tropical  countries.  It  occurs  in  India,  China,  Japan,  Aus- 
tralia, Queensland,  the  Islands  of  Polynesia  (with  the  exception  of 
the  Sandwich  Islands),  Egypt,  Algeria,  Tunis,  Madagascar,  Zanzi- 
bar, Sudan,  &c.,  the  south  of  the  United  States  of  America, 
Brazil,  the  Antilles,  &c.3 

The   disease   (filariasis)   presents   a   series   of  very   diverse   symp- 


1  Journ.  of  Tropical  Medicine,  April  I4th,  1900,  p.  219. 

-Brit.  Med.  Journ.,  June  i6th,  1900. 

3  According"  to  Font,  indigenous  filariasis  also  occurs  in  Europe  ;  he  reports  the 
case  of  a  man  who,  since  his  eighteenth  year,  had  suffered  from  haemato-chyluria  and 
enlargement  of  the  scrotum,  and  whose  blood  exhibited  nlariae.  With  the  exception 
of  a  short  time  spent  in  San  Sebastian,  the  patient  had  never  left  his  birthplace  (Canet 
de  Mar,  41  km.  north  of  Barcelona).  Two  further  cases  of  haemato-chyluria  were 
reported  from  the  same  district,  but  no  microscopical  examination  of  the  blood  and 
urine  was  undertaken  in  these  (Font,  M.  "  De  la  Filariosis  :  expos,  del  primer  caso 
esporad.  observ.  en  Europa,"  Riv.  dene.  med.  de  Barcelona,  1894,  pp.  73  and  97  '•  re*- 
in  C.  f.  B.  u.  P.,  xvi.,  p.  85).  In  a  case  of  indigenous  elephantiasis  originating  in 
Brest,  the  blood  examination  had  a  negative  result  (Guyot,  "  Un  cas  d'elephant.  tndig. 
obs.  a  Brest,"  Arch.  med.  nav.,  1892,  Iviii.,  p.  192  ;  "  Autrc  cas  d'eleph.  des  arabes 
en  Breta°ne,"  Ibid.,  1893,  ^XM  P- •II5)- 


THE   ANIMAL    PARASITES   OF    MAN 

toms.  During  the  initial  stages,  which  may  extend  over  a  long 
period,  there  are  no  subjective  disorders ;  the  infection  is  only 
demonstrated  by  the  filarise  in  the  blood  ;  sooner  or  later  anaemia, 
enlargement  of  the  spleen  and  fever  set  in  ;  lymphatic  tumours 
also  appear  in  various  situations,  the  testicles  or  spermatic  cord 
being  mostly  attacked  in  men.  In  consequence  of  engorgement 
of  the  lymph  vessels  it  is  not  uncommon  for  a  sort  of  elephan- 
tiasis to  develop,  generally  in  the  scrotum  and  lower  extremities  ; 
enlargements  of  the  lymphatic  glands  are  also  set  up  ;  later  on 
chyluria  or  haematuria,  inflammation  of  the  kidneys  and  other 
parts  of  the  urinary  apparatus,  as  well  as  of  the  peritoneum, 
occur. 

LITERATURE. 
DEMARQUAY.      Note    sur    une    tumeur    de    bourse.     .     .     .     renferm.     .     .     .     des 

helmintes  nematoides.     (Gaz.  rued.,   Paris,   1863,   [3],  xviii.,  p.  665). 
LEWIS,   T.   R.      On  a  Haematozoon   Inhabiting  Human  Blood.    Calcutta,  1872.      II. 

ed.,  ibid.,    1874. 

The  Patholog.  significance  of  Nematode  Hsematozoa.      Calcutta,    1874. 
COBBOLD,   T.    S.      The   life-history   of  Filaria  Bancrofti.     (Journ.   Linn.    Soc.    Zcol., 

1879,   xiv.,   p.   356.) 
MANSON,   P.      The  Metamorph.  of  Fil.  Sang.  Horn,  in  the  Mosquito.     (Transact.   Linn. 

Soc.,  London,    1884  [2],  ii.,   pp.    10  &    367.) 

The  Filaria  Sang.   Horn.,   &c.,  London,    1883,    186  pp.,   8°,    10  pi. 
SCHEUBE.      Die  Filariakrankheit.     (Volkmann's  Samml.   kl.   Vortr.,   No.   232,    1883). 
HEBRA,   v.      Die  Elephantiasis  Arabum.     (Wien   Klinik,    1885,   Nos.    8   and  9.) 
BOURNE,    A.    G.     Not.    on    Fil.    Sang.  Horn.,    with   descr.    of    a  Male   Spec.     (Brit. 

Med.    Journ.,    1888,   No.    1429.) 

SIBTHORPE.      On  the  ad.   male  of  Fil.   Sang.   Horn.    (Ib.,    1889,  No.    1485.) 
THIESING,  H.      Beitr.  z.   An.  d.  Fil.  Sang.  Horn.     In-Diss.  Basel  (Leipzig,   1892.) 
LINSTOW,    v.     Ueb.    d.    Art.    d.    Blutfil.    d.    Mensch.       (Zool.    Anzgr.,     IC.CG,    xxiii., 

p.    76.) 
BANCROFT,  TH.      On  the  Metamorph.   of  the  Young  Form  of  Fil.   bancrofti,   Cobb., 

in    the    body    of   Culex    ciliaris.       (Proc.    R.    soc.,    N.  S.    Wales,    1900,    xxiii., 

p.    48.) 
Low,    G.   C.      A   Rec.    Obs.  on   Fil.    noct.   in   Culex.      (Brit.    Med.    Journ.,    1900,    i., 

p.    1456.) 

MAITLAND,   J.      Note  on  the  Etiol.   of  Filariosis.       (Ibid.,    1902,  p.    537.) 
BLANCHARD,   R.     Transmiss.  de  la  filariose  par  les  moustiques.     (Arch,   de  parasit., 

1900,  iii.,  p.   280.) 

GRASSI,  B.,  and  G.  NOE.     L.c.       (Cf.  Fil.  immitis.) 
SAMBON,  L.  W.      Filaria  Bancrofti  and  Filaria  immitis  (Lancet,  1902,  p.  422.) 

4.     Filaria  diurna,  P.  Manson,  1891. 
Syn.  :  Filaria  sanguinis  hominis,  var.  major,  Mans.,  1891. 
Is    only  known    in   its  larval   stage,   which    resembles    that    of 
Filaria    bancrofti  ;   nevertheless,  it   is    distinguished   from  the  latter 
by    the    fact    that    in    it    the    granulation    of    the  intestine  is  lack- 
ing, and  that  it  appears  in  the  blood  DURING  the  day  only.     This 
appears  to  indicate  that  the  larvae  are  liberated  by  a  blood-sucking 
insect   flying   in   the   day   time ;     the   so-called   mangrove    flies    are 
suspected  to  be  the  intermediary  hosts. 

This   filaria   was   found   by   P.   Manson   in    the   blood   of   several   negroes 


FILARIA   PERSTANS  293 

from  the  West  Coast  of  Africa  (Congo).     The  author  seeks  to  connect  these 
filariae  with  Filaria  loa  (c.f.  below),  but  the  proofs  thereof  are  still  lacking. 

LITERATURE. 

MANSON,    P.      The    Filaria    Sang.    Horn.,   Major    and    Minor,    two   New    Species    of 

Haematozoa.       (The    Lancet,     1891,    i.,   p.    4.      Ref.    im.    Centralbl.    f.    Allg. 

Path.,   ii.,   p.    298.) 
MANSON,   P.     Geograph.   Distribution.     ...     of    Fil.   Sang.   Horn.   Diurna  and  of 

Fil.    Sang.    Horn.    Persians.       (Transact.  Seventh    Intern.    Congr.    of    Hygiene 

and   Demogr.,   London,    1891,  i.,   p.   79,    1893.) 
MANSON,    P.      Trop.   Diseases.      Lond.,    1898. 

5.     Filaria  perstans,  P.  Hanson,  1891. 
Syn.  :    Filaria  sanguinis  hominis,  var.  minor,  Manson,   1891. 

This  parasite  is  likewise  only  known  in  its  larval  stage  from 
the  blood  of  negroes  of  West  Africa.  It  is  distinguished  from 
other  blood  filariae  of  man  by  its  small  size  (0*2  mm.  in  length), 
great  motility  and  contractility,  absence  of  sheath,  as  well  as  by 
the  fact  that  it  may  be  observed  in  the  blood  of  patients  at  all 
times  of  the  night  and  day.  A  few  patients  suffered  from  "negro 
lethargy."  The  author  is  of  opinion  that  these  Nematodes  cause 
also  the  skin  disease  known  by  the  negroes  as  craw-craw,  the 
larvae  of  the  Nematodes  appearing  in  the  papules.  According  to 
Firket,  blood  filariae  are  very  frequent  (55  per  cent.)  in  the 
negroes  of  various  districts  of  the  Congo  region,  even  in  children  ; 
the  persons  affected  had  no  skin  eruption,  and  were  for  the  most 
part  in  good  health.  One  of  the  persons  had  already  been  in 
Europe  six  years  and  another  eighteen  months. 

[Filaria  perstans,  in  its  larval  form,  was  discovered  by  Sir 
Patrick  Manson  in  1891  in  the  blood  of  a  West  African  negro 
suffering  from  sleeping  sickness,  who  was  under  the  care  of  Sir 
Stephen  Mackenzie  in  the  London  Hospital,  Later,  Manson  found 
it  in  blood  films  from  natives  of  the  Congo  and  Old  Calabar.  In 
1897,  he  examined  the  blood  of  Carib  Indians  sent  by  Dr.  Ozzard 
from  British  Guiana,  and  found  larval  filariae  closely  resembling 
those  of  F.  perstans,  together  with  other  sharp-tailed  larvae  slightly 
larger  in  size  but  equally  deprived  of  sheath.  The  co-existence  of 
blunt  and  sharp-tailed  filarial  larvae  in  the  same  host  was  some- 
what puzzling,  and  Manson  provisionally  gave  to  these  filariae  the 
name  of  Filarice  ozzardi. 

In  1898,  at  the  post-mortem  examination  of  two  Demerara 
Indians,  Dr.  Daniels  found  the  adult  form,  both  male  and  female, 
of  the  blunt-tailed  larvae,  and  soon  after  the  adult  forms  of  the 
sharp-tailed  larvae.  This  showed  that  the  differently  shaped  larvae 
belonged  to  two  different  species,  one  of  which  was  undoubtedly 


294  THE   ANIMAL   PARASITES   OF   MAN 

a  new  species  and  retained  the  name  of  F.  ozzardi  suggested  by 
Manson.  Adult  forms  of  the  African  blunt- tailed  larvae  were  next 
found  by  Mr.  O'Neil  at  the  necroscopy  of  a  Congolese  patient 
who  died  from  sleeping  sickness  in  Charing  Cross  Hospital,  and 
Manson,  after  a  comparison  between  these  and  the  British  Guiana 
specimens,  came  to  the  conclusion  that  they  were  identical. 

The  larval  Filaria  perstans  measures  on  an  average  O'2  mm.  in 
length  by  0*0045  mm.  in  breadth  ;  it  has  a  blunt,  truncated  tail, 
and  possesses  no  sheath.  The  head  is  provided  with  a  retractile 
fang.  The  anterior  gap  in  the  central  column  of  cells  (Manson's 
V  spot)  is  at  about  0*03  mm.  from  the  cephalic  extremity. 
There  is  no  marked  tail  gap.  Having  no  sheath,  these  larvae  are 
able  to  move  rapidly  and  freely  all  over  the  slide.  The  larvae 
of  F.  perstans  observe  no  periodicity.  Their  numbers  in  the 
peripheral  circulation  may  vary  considerably,  but  there  is  no 
marked  difference  between  day  and  night.  Their  special  seat  of 
selection  is  not  the  peripheral  blood,  but  that  of  the  heart,  lungs, 
aorta  and  other  large  vessels.  They  are  never  found  in  the 
spleen,  and  only  rarely  in  the  liver  and  pancreas. 

The  adult  female  F.  perstans  measures  70  to  80  mm.  in 
length  by  O'i2  mm.  in  breadth.  The  head  is  club-shaped  and 
measures  0*07  mm.  in  diameter.  The  genital  pore  opens  at  o-6 
mm.  from  the  head.  The  tail  is  curved  and  presents  a  cuticular 
thickening,  which  forms  two  tiiangular  appendages.  The  anus 
opens  at  the  apex  of  a  papilla  situated  in  the  concavity  of  the 
curve  formed  by  the  tail.  The  diameter  of  the  tail  just  before 
termination  is  0*02  mm. 

The  adult  male  measures  45  mm.  in  length  by  cro6  mm.  in 
breadth.  The  diameter  of  the  head  is  0-04  mm.  Close  to  the 
opening  of  the  cloaca  there  are  four  pairs  of  pre-anal  papillae 
and  one  pair  of  post-anal  papillae.  Two  unequal  spicules  may 
sometimes  be  seen  protruding  from  the  orifice. 

The  adult  worms  inhabit  the  connective  tissue  at  the  base  of 
the  mesentery.  To  find  them  the  mesentery  should  be  removed, 
placed  in  a  2  per  cent,  solution  of  formalin,  and  then  carefully 
examined  at  leisure. 

Filaria  perstans  has  a  wide  geographical  distribution.  In 
Africa  it  is  very  common  in  certain  districts  along  the  west 
coast.  Drs.  Annett,  Button  and  Elliott  report  its  presence  at 
Sierra  Leone,  on  the  Kroo  Coast,  on  the  Ivory  Coast,  on  the 
Gold  Coast,  at  Lagos,  in  Northern  and  Southern  Nigeria  ;  Manson 
found  it  in  slides  of  blood  from  Old  Calabar  and  from  the  Congo. 


FILARIA    PERSTANS  295 

Professor  Firket  has  shown  that  in  certain  districts  on  the  Congo 
it  occurs  in  half  the  population.  Moffat,  Cook,  Hodges  and  Low 
have  found  the  parasite  to  be  extremely  common  in  many  areas 
in  Uganda.  Low  found  it  in  86  per  cent,  of  the  population  in 
the  Sese  Islands  to  the  south  of  Entebbe.  Moffat  and  Low  found 
it  in  76  per  cent,  of  the  people  of  Unyoro  ;  Daniels  found  one 
case  in  a  native  of  British  Central  Africa  on  Lake  Nyassa.  On 
the  east  coast  of  Africa  it  is  not  found  in  the  towns  of  Zanzibar 
and  Mombasa,  neither  is  it  found  in  the  country  of  the  Masai  ; 
nor  amongst  the  Kavirondo,  who  dwell  along  the  north-east  shores 
of  Lake  Victoria. 

In  South  America,  Filaria  perstans  is  very  common  amongst 
the  aboriginal  Indians  in  the  interior  of  British  Guiana,  How- 
ever, it  is  not  found  in  Georgetown  and  in  New  Amsterdam, 
neither  is  it  found  in  the  cultivated  strip  of  coast  lying  between 
these  two  towns,  but  it  is  common  on  the  coast  further  north 
near  the  Venezuelan  boundary,  where  the  forests  stretch  to  the 
sea.  The  Waran  Indians,  who  live  at  the  mo,uth  of  the  Waini 
river,  harbour  this  parasite.  Dr.  Low,  while  studying  filarial 
diseases  in  the  West  Indies  in  1901,  never  met  with  Filaria 
perstans  in  these  islands,  although  he  examined  the  blood  of 
large  numbers  of  individuals  in  St.  Kitts,  Dominica,  St.  Lucia, 
Barbadoes,  St.  Vincent,  Grenada,  and  Trinidad. 

Topographically,  Filaria  perstans  is  found  only  in  areas  covered 
by  dense  forest  growth  and  abounding  in  swamps.  In  Kavirondo, 
where  the  forest  disappears  and  the  land  is  covered  with  scrub 
and  short  grass,  it  is  not  found  :  likewise  it  is  not  found  on  the 
grassy  plains  of  the  highlands  of  British  East  Africa.  Towns  and 
cultivated  areas  are  free  from  it. 

In  order  to  find  the  intermediary  host  of  Filaria  perstans,  Dr. 
Low  made  numerous  and  careful  experiments  with  many  different 
species  of  mosquitoes  (Culex  fatigans,  M.  atratus,  C.  viridus,  C. 
luteolateralis,  C.  quasigelidus  ;  Anopheles  argyrotarsis,  A.  costalis, 
A.  funestus  ;  Stethomyia  nimbus  ;  J anthinosoma  musica  ;  Mansonia 
africanus  ;  Uranotcenia  cceruleocephala  ;  Tceniorhynchus  fuscopen- 
natus)  and  other  blood-sucking  insects  (Pulex  irritans,  P.  pene- 
trans,  Pediculus  capitis  and  P.  vestimentonim).  These  insects  were 
either  caught  in  the  huts  of  infected  persons,  or  they  were  reared 
from  the  larva  and  then  fed  on  infected  persons.  After  a  certain 
time  they  were  dissected,  but,  with  one  exception,  the  results 
were  negative.  In  one  isolated  instance  two  developmental  forms 
were  seen  between  the  thoracic  muscles  of  a  Tceniorhynchus  fusco- 


296  THE    ANIMAL    PARASITES   OF    MAN 

Pennatus  reared  from  the  larva  and  fed  on  infected  persons.  This 
seems  to  prove  that  Filaria  perstans  in  its  proper  intermediary 
host,  like  Filaria  bancrofti,  develops  between  the  thoracic  muscles. 
Dr.  Christy  suggests  that  the  true  intermediary  host  of  Filaria 
perstans  is  Ornithodoros  monbata,1  a  tick  of  the  sub-family  Argasince. 
However,  he  gives  no  evidence  in  support  of  this  view,  which  is 
contradicted  by  facts  of  geographical  distribution.  I  am  inclined 
to  think  that  the  intermediary  host  of  F.  perstans  is  to  be  found 
amongst,  the  blood-sucking  flies. 

At  one  time  F.  perstans  was  incriminated  as  a  possible  factor 
in  the  etiology  of  sleeping  sickness.  Recent  researches  have 
proved  that  it  has  no  causal  connection  with  the  disease.  F. 
perstans  seems  to  have  no  pathological  importance.  The  presence 
of  the  adult  parasites  in  the  mesentery  appears  to  cause  no  harm 
to  the  host.— L.  W.  S.] 

LITERATURE. 

O'NEIL.  On    the    Pres.    of    a    Filaria    in    "Craw-craw."       (The    Lancet,     1875,    i., 

p.  265.) 

MANSON,  P.      L.  c. 

FIRKET,  C.    M.      Filariose    du    sang    chez    les    negres    du    Congo.      (Bull.    Ac.  roy, 

Med.    de    Belg.,    1895,  4    Ser.,    ix.,      Ref.    in   C.    f.    B.,    P.    u.    Inf.    [i],    xix., 

p.  791.) 

HENRY.  Rem.   on   Filaria.     (Proc.   Ac.   Nat.   Sc.,   Philadelphia,    1896,   p.    271.) 

BRUALT,  J.     Note  sur  le  Craw-craw.       (Ann.    Dermatol.,   Paris,    1899,   p.    226.) 

6.     Filaria  demarquayi,  Manson,   1895. 

Of  this  form  also  we  know  only  the  larvae  circulating  in  the 
peripheral  blood.  They  are  found  in  the  blood  night  and  day, 
are  provided  with  a  sheath,  but  are  only  half  the  length  of 
the  larvae  of  Filaria  bancrofti.  They  have  been  observed  in  blood 
preparations  from  natives  of  the  Island  of  St.  Vincent  (Lesser 
Antilles,  West  Indies).  The  same  species  is  also  supposed  to  occur 
in  Brazil  and  Africa  (Niger). 

{Filaria  demarquayi  was  discovered  by  Sir  Patrick  Manson  in 
1895  in  blood  films  from  natives  of  St.  Vincent,  West  Indies. 
Manson  found  the  larval  form  of  this  filaria  in  ten  out  of  152 
slides  received  from  Dr.  Newsan. 

The  larva  of  Filaria  demarquayi  measures,  according  to  Dr. 
G.  C.  Low,  o'2  mm.  in  length  by  0*005  mm.  in  breadth  ;  it  is 
sharp-tailed,  and  has  no  sheath.  Its  movements  are  very  active, 
and  the  absence  of  a  sheath  enables  it  to  glide  along  freely  all 

1  [Professor  Neumann  informs  me  the  correct  name  for  this  tick  is  Ornithodoros 
savignyi  (Audouin).  The  specimens  received  from  Uganda  all  belong  to  Neumann's 
variety  caeca.  ( Vide  Second  Report  Eco.  Zool.  p,  113,  1904.  Theobald). — F.V.T.] 


FILARIA   OZZARDI  297 

over  the  slide.  It  observes  no  periodicity,  being  present  in  the 
peripheral  circulation  both  by  day  and  by  night.  As  a  rule, 
some  eight  or  ten  parasites  are  found  in  an  ordinary  preparation. 
Sometimes  hundreds  of  these  larval  filariae  may  be  counted  on 
every  slide. 

Identical  larvae  have  been  seen  by  Manson,  Galgey,  Low,  and 
St.  George  Gray  in  the  blood  of  natives  of  St.  Lucia,  and  Low 
found  them  also  in  the  blood  of  natives  of  Dominica  and  Trinidad. 
Manson  has  seen  this  parasite  or  one  exceedingly  like  it  in  the 
blood  of  the  natives  of  New  Guinea.  The  larvae  of  F.  demarquayi 
are  indistinguishable  from  those  of  F.  ozzardi. 

The  adult  female  form  of  F.  demarquayi  was  found  by  Dr. 
Galgey  in  the  body  of  a  native  of  St.  Lucia  in  whose  blood  the 
larvae  had  been  found  during  life.  Five  adult  females  were  found 
in  the  connective  tissue  of  the  mesentery.  Two  of  these  speci- 
mens were  presented  to  the  London  School  of  Tropical  Medicine, 
and  described  by  Dr.  Daniels. 

The  adult  female  Filaria  demarquayi  measures  from  65 — 80 
mm.  in  length  by  0-21 — 0*25  mm.  in  breadth.  The  head  has  a 
diameter  of  from  0-09 — 0*1  mm.  The  mouth  is  terminal.  The 
genital  pore  opens  at  0^76  mm.  from  the  head.  The  alimentary 
canal  is  nearly  straight  and  terminates  in  an  anus,  which  is  sub- 
terminal.  The  opening  of  the  anus  is  marked  by  a  slight  papilla. 
The  tail  is  curved.  It  rapidly  diminishes  in  size  just  below  the 
anal  papilla.  A  marked  cuticular  thickening  covers  the  tip  of  the 
tail.  The  diameter  near  the  tip  of  the  tail  before  its  termination 
is  O'O3  mm.  F.  demarquayi  is  a  thicker  worm  than  F,  perstans. 
It  differs  from  F.  bancrofti  and  F.  ozzardi  in  the  greater  size  of 
the  head,  in  the  smaller  tail  and  particularly  in  the  marked 
cuticular  thickening  at  the  tip  of  the  tail.  This  thickening  is 
knobby,  but  the  divisions  are  not  so  well  marked  as  in  F.  perstans. 

The  male  of  Filaria  demarquayi  has  still  to  be  found.  The 
intermediary  host  has  not  been  discovered.  The  distribution  of 
this  filaria  is  singularly  limited  both  geographically  and  topo- 
graphically.— L.  W.  S.] 

7.     Filaria  ozzardi,  Manson,  1897. 

The  larvae  are  found  in  the  blood  of  natives  of  British  Guiana  ; 
they  measure  0*173 — 0*240  mm.  in  length  by  0*0043 — 0*0050  mm. 
in  breadth,  and  have  no  sheath.  The  caudal  extremity  is  obtuse, 
rarely  pointed.  They  appear  in  the  peripheral  bloodjat  all  times  of 


298  THE    ANIMAL    PARASITES    OF    MAN 

the  day.     The    differentiation    of     Hanson's    four    species    remains 
uncertain  as  long  as  the  adult   stage  is  unknown. 

[Filaria  ozzardi  was  discovered  by  Sir  Patrick  Manson  in  1897 
in  blood  films  prepared  by  Dr.  Ozzard  from  aboriginal  Carib 
Indians  inhabiting  the  back  country  of  British  Guiana.  At  least 
half  of  the  slides  examined  contained  larval  filariae  ;  some  slides 
only  one  or  two,  other  slides  as  many  as  forty  or  fifty.  These 
larval  filariae  were  not  all  alike,  they  differed  slightly  in  size  and 
in  the  shape  of  their  posterior  extremity.  Five  out  of  six 
presented  a  blunt  tail,  the  others  had  a  sharp  tail.  Dr.  Daniels 
proved  that  the  blunt-tailed  larvae  were  the  young  of  Filaria 
Persians,  because  he  found  the  adult  F.  perstans,  both  male  and 
female,  at  the  post-mortem  examination  of  two  Demerara  Indians, 
whose  blood,  during  life,  contained  both  blunt  and  sharp-tailed 
larvae.  Later,  Dr.  Daniels  found,  at  the  post  mortem  of  another 
native  in  whose  blood  both  the  blunt  and  sharp-tailed  larvae  had 
been  found,  a  few  adult  specimens  of  Filaria  perstans,  and,  in 
addition,  a  female  and  portion  of  a  male  worm  of  a  new  species 
closely  resembling  Filaria  bancrofti  in  shape  and  size,  but  differing 
from  it  on  account  of  the  bulbous  termination  of  its  tail.  This 
parasite  was  presumably  the  parental  form  of  the  sharp-tailed 
larvae  previously  found  in  the  peripheral  circulation  of  the  host. 

The  larval  form  of  Filaria  ozzardi  measures  o-2i  mm.  in  length 
by  0-005  mm-  m  breadth,  it  has  a  sharply-pointed  tail  and  no 
sheath  ;  it  observes  no  periodicity. 

The  adult  forms  have  been  found  only  once  by  Dr.  Daniels  in 
the  subserous  connective  tissue  of  the  anterior  abdominal  wall. 
The  female  measures  81  mm.  in  length  by  o'2i  mm.  in  breadth.  The 
head  has  a  diameter  of  0-05  mm.,  the  genital  pore  opens  at  071 
mm.  from  the  head.  At  this  point  the  diameter  of  the  body  is 
0-12  mm.  The  anus  is  at  0*23  mm.  from  the  tail.  The  tail  is 
bluntly  truncated  and  slightly  bulbous,  it  presents  no  cuticular 
thickening.  The  diameter  near  the  tip  of  the  tail  before  ter- 
mination is  o'O45  mm. 

The  male  worm  measures  38  mm.  in  length  by  O'lq  mm.  in 
breadth.— L.  W.  S.] 

LITERATURE. 

MANSON,   P.      On  Certain  New  Spec,  of   Nemat.   Haemat.  occ.  in    America.     (Brit. 

Med.   Journ.,   London,    1897,   &•>   P-    l%37-) 
DANIELS,  C.  W.      Fil.    and    Fil.    Disease    in    Brit.    Guin.      (Ib.,    1898,    i.,   p.    ion. 

ii.,  p.   878.) 
GALGEY,  O.     Fil.   Dem.  in  St.  Lucia.       (Ib.,    1899,  i.,  p.    145.) 


FILARIA    MAGALHAESI 


299 


8.     Filaria  magalhaesi,  R.  Blanchard,  1895. 

Syn.  :  Filaria  bancrofti,  v.  Linstow,  1892  ;  Fil.  bancrofti,  P.  S.  de  Magalhaes, 
1892,  nee.  Cobbold,  1877. 

The  male  measures  83  mm.  in  length  by  0*28 — 0-40  mm.  in 
breadth  ;  the  cuticle  is  firm  and  delicately  striated.  The  anterior 
extremity  is  rounded  off,  and  has  no  papillae  ;  the  posterior  ex- 
tremity exhibits  a  double  curve,  with  four  pre-anal  and  four  post-anal 
papillae  on  each  side.  These  are  large  and  have  a  villous  appear- 
ance. The  mouth  is  round  and  unarmed,  the  pharynx  measures 
i  mm.  in  length,  is  cylindrical,  very  muscular,  and  its  hinder  part 
is  dilated.  The  anus  is  situated  0*11  mm. 
in  front  of  the  posterior  border.  There  are 
probably  two  uneven  spicules  ;  one  only,  how- 
ever, is  known — apparently  the  shorter  one 
— the  length  of  which  is  given  as  0*17— 
0*23  mm. 

The  female  measures  15*5  mm.  in  length 
and  0*6 — 0*8  mm.  in  breadth;  the  rings  of 
the  cuticle  are  0-005  mm-  apart  (in  the 
male  0*003  mm.  apart)  ;  the  anterior  ex- 
tremity is  slightly  thickened  and  club-like, 
the  posterior  extremity  is  slender,  and  termi- 
nates obtusely  ;  the  lateral  ridge  is  0*127  mm- 
in  breadth  (that  of  the  male  0*007 — 0*008 
mm.)  ;  the  anus  opens  0*13  mm.  in  front  of 
the  posterior  border,  the  vulva  is  2*5  mm. 
distant  from  the  mouth,  the  ovaria  are  two 
convoluted  tubes.  The  eggs  measure  0*038  : 

0*014   mm  ;      the   larvae    0*30 — 0*35    mm.    in   length,    0*006    mm.    in 
breadth,   with   a   transversely   striated   cuticle. 

This  species  was  first  discovered  at  a  post  mortem,  in  the  left  ventricle, 
by  J.  P.  Figueira  de  Saboia  in  Rio  de  Janeiro,  and  has  been  described  by 
P.  S.  de  Magalhaes. 


FIG.  198.  —  Filaria 
magalhaesi ;  posterior 
extremity.  (After  v. 
Linstow.) 


LITERATURE. 

MAGALHAES,  P.  S.  de.  Descrip.  da  uma.  esp.  de  filar,  encontr.  no  cora<;ao 
humno.  (Rev.  d.  curs.  prat,  e  theoric,  faculd  de  med.  Rio  de  Janeiro, 
1887,  iii.,  p.  126.) 

LINSTOW,   v.       Ueber  Fil.   bancrofti,   Cobb.       (C.   f.   B.   u.    P.,    1892,   xii.(   p.    88.) 
MAGALHAES,   P.   S.   de.       Die  Fil.   bancrofti  u.   Fil.  immitis.       (Ib.,  p.    511.) 
LINSTOW,  v.       Art.  d.   Blutfil.  d.  Mensch.       (Zool.    Anzg.,    1900,   xxiii.,  p.  76.) 


300  THE    ANIMAL    PARASITES   OF    MAN 

9.    Filaria  loa,  Guyot,  1778. 

Syn.  :  Filaria  oculi,  Gerv.  et.  v.  Ben.,  1859  >  Dracunculus  oculi,  Diesing,  1860  ; 
Dracunculus  loa,  Cobbold,  1864  j  Filaria  subconjunctivalis,  Guyon,  1864. 

The  male  measures  22 — 30  mm.  in  length,  and  0*3 — 0*4  mm. 
in  breadth  ;  the  cuticle  is  not  striated,  but,  with  the  exception 
of  the  anterior  and  posterior  extremities  (1-5  mm.)  is  beset  with 
numerous  irregularly  distributed  protuberances.  The  anterior 
extremity  is  somewhat  narrowed,  and  in  front  is  conical  and 
transversely  obtuse.  On  each  side  of  the  posterior  border  of  the 
conical  part  is  a  small  papilla  corresponding  to  the  dorsal  and 
ventral  median  ridges.  The  posterior  extremity  is  attenuated  and 

somewhat  curved  ventrally ;  the  anus 
is  0-082  mm.  distant  from  the  rounded 
posterior  border.  In  front  of  the  anus 
on  each  side  are  three  globular  and 
pedunculated  papillae  of  different  sizes, 
set  close  one  behind  the  other  ;  behind 
the  anus  on  either  side  are  two  smaller 
papillae  of  a  different  shape  ;  the  ante- 
rior one  resembles  the  pre-anal  papillae 
in  form,  but  is  smaller ;  the  posterior 
FIG.  199.— Filaria  loa.  The  one  js  conical,  and  rests  on  the  cuticle, 

anterior  end  of  the  male,  mag-  , 

nified.    (After  R.  Biajichard.)        with  a  broad  base.     The  spicules  differ 

but  little  in  their  length. 

The  female  measures  32 — 41  mm.  in  length,  by  0*5  mm.  in 
breadth.  It  is  also  beset  with  irregularly  distributed  chitinous 
bosses,  which  in  places  stand  close  to  each  other,  and  extend  to 
the  anterior  extremity ;  posteriorly  they  become  less  frequent, 
but  are  not  entirely  absent.  The  anterior  extremity  is  conical, 
the  posterior  one  straight,  attenuated,  rounded  off.  The  vulva 
apparently  lies  at  the  border  of  the  first  and  second  quarter 
of  the  body ;  the  vagina,  3  mm.  in  length,  forks  off  into  two  long 
(10  cm.)  tubes,  extending  almost  throughout  the  entire  length  of 
the  body,  the  narrow  end  of  which  are  the  ovaria  ;  they  contain 
eggs  in  the  most  various  stages  of  development,  as  well  as  hatched- 
out  larvae,  0-253 — 0*262  mm.  in  length,  and  0*0047 — 0-005  mm- 
in  breadth.  Their  anterior  extremity  is  rounded,  the  posterior 
extremity  is  slender  and  awl-shaped  ;  the  cuticle  is  smooth.  In 
addition  to  the  rudiment  of  the  intestine  the  rudiment  of  the 
generative  glands  also  can  be  recognised  0*08  mm.  behind  the 
anterior  extremity. 


FILARIA    LOA  301 

Filaria  loa  lives  in  the  connective  tissue  of  the  conjunctive 
between  it  and  the  bulbus  oculi ;  sometimes,  however,  it  retires 
into  the  depth  of  the  orbit,  to  emerge  nearer  to  the  surface  after 
a  longer  or  shorter  time  ;  the  wandering  of  the  worm  also  from 
one  eye  to  the  other  beneath  the  skin  of  the  bridge  of  the  nose 
has  been  observed,  and  occasionally  the  parasite  has  also  been 
known  to  appear  in  other  parts  of  the  body  within  the  subcuta- 
neous connective  tissue,  notably  in  the  fingers.  It  is  doubtful 
whether  it  also  occurs  in  the  eye-ball.  Several  observations  have 
been  reported,  some  relating  to  a  comparatively  long  worm,  which 
may  have  been  either  Filaria  loa  or  Filaria  medinensis. 


FIG.   200. — Filaria  loa  ;  to  the  left  is  the  posterior  extremity  of  a  male  ;  to  the 
right   the  anterior  extremity  of  a  female.      Magnified.      (After  R.   Blanchard.) 


The  first  accounts  of  Filaria  loa — long  since  forgotten — were  reported 
by  Pigafetta,  and  are  contained  in  a  book  of  travels  on  the  Congo  printed 
in  1598.  In  an  accompanying  illustration  is  depicted,  not  only  the  ancient 
method  of  extraction  of  the  Medina  worm,  but  also  the  operative  removal 
of  the  filaria  from  the  conjunctiva.  Subsequently  the  presence  of  the 
worm  in  negroes  was  confirmed  by  Bajon  in  Guiana  (1768)  and  by 
Mongin  in  Mariborou  (San  Domingo)  ;  likewise  in  a  negro  (1770).  At  about 
this  time  a  French  ship's  doctor,  Guyot,  was  cruising  on  the  West  Coast 
of  Africa ;  he  observed  the  parasite  termed  "  loa  "  by  the  natives  and 
learned  that  it  was  frequent  in  the  negroes  of  the  Congo  district.  Since 
that  time  numerous  observations  have  been  reported.  It  was  formerly 
common  in  South  America,  where  the  parasite  was  imported  by  slaves,  but 
it  disappeared  when  the  traffic  ceased  ;  it  is  particularly  prevalent  in  the 
Congo,  where  it  occurs  not  only  in  natives,  but  also  in  Europeans.  During 


302  THE    ANIMAL    PARASITES    OF    MAN 

recent   times  it  has  repeatedly  been  observed  in  Europe  in  negroes   as   well 
as  in  white  men  who  have  lived  on   the  West  Coast  of  Africa. 

Nothing  is  known  regarding  the  development  of  Filaria  loa. 
Manson  advances  the  hypothesis  that  its  larva  is  Filaria  diurna, 
but  this  requires  confirmation  ;  however,  in  the  few  cases  in  which 
the  blood  of  the  host  of  Filaria  loa  has  been  examined  blood 
filarise  have  not  been  found  ;  in  the  case  adduced  by  Manson  the 
patient  certainly  had  filariae  in  the  blood,  but  at  the  time  of 
observation  had  no  Filaria  loa. 

The  presence  of  this  worm  sometimes  causes  no  inconvenience,  but,  as 
a  rule,  like  any  foreign  body  introduced  into  the  conjunctival  sac,  induces 
symptoms  of  inflammation  which  may  become  periodically  aggravated. 

Nematodes  of  the  most  various  sizes  have  been  repeatedly  observed  in 
the  anterior  chamber  of  the  eye  as  well  as  in  the  substance  of  the  lens 
and  vitreous  humour.  Thus  Mercier  (1771  and  1774)  removed  a  filaria  from  the 
anterior  chamber  of  the  eye  of  two  negroes  in  St.  Domingo,  of  which  one 
specimen  measured  35  mm.  in  length.  There  is  a  further  statement  of 
Barkan  (1876),  who  extracted  a  filaria  from  the  chamber  of  the  eye  of  an 
Australian  in  San  Francisco.  For  a  few  weeks  Coppez  and  Lacompte  (1894) 
had  a  little  negro  girl,  2|  years  of  age,  under  observation,  in  whose  eye 
there  was  an  immature  nematode  measuring  15-2  mm.  in  length,  and 
which  was  removed.  It  is  difficult  to  say  which  species  {Filaria  loa  or 
Filaria  medinensis}  was  in  question  in  these  cases. 

LITERATURE. 

PIGAFETTA.     Vera  descr.  regni  afric.,  quod  tarn  ab  incolis  quam  a  Lusitanis  Congus 

appellatur.  Francofurti,  1598. 
BAJON.     Mem.  pour  servir  a  1'hist.  de  Cayenne  et  de  la  Guyane  franc.,  1768,  i.,  p.  325. 

Abhdlg.  v.  d.  Krankh.  a.  d.  Insel  Cayenne  u.  d.  franz.  Guyana.     Erfurt,  1781. 
MONGIN.     Obs.  sur  un  ver  trouve  dans  la  conjunct,  a  Mariborou.     (Journ.  de  med., 

1770,  xxxii.,  p.  338.) 

GUYOT  in  Arrachart.  Mem.,  diss.  et  observ.  de  chirurgie,  Paris,  1805,  P-  22<&- 
LUDWIG,  H.,  and  TH.  SAEMISCH.     Ueb.  Fil.  loa  i.  Auge  d.  Mensch.     (Z.  f.  w.  Z.,  1895, 

lx.,  p.  726.) 
BLANCHARD,  R.     Nouv.  cas  de  Fil.  loa  (Arch,  de  paras.,  1899,  ii.,  p.  504). 

10.     Filaria   oculi  humani,   v.    Nordmann,  1832 ;   Filaria  lentis, 

Diesing,  1851. 

The  sexless  nematodes  observed  in  the  lens  of  the  human  eye 
are  termed  Filaria  oculi  humani.  Only  three  cases  are  known, 
v.  Nordmann  observed  very  small  round  worms  in  the  lens  of  a 
man  and  woman  with  cataract,  and  Gescheidt  once  found  three 
specimens  in  the  lens  of  a  woman  similarly  affected. 

The  demonstration  of  nematode-like  formations  in  the  vitreous 
remains  uncertain  even  when  movements  are  observed,  and  when 
they  cannot  be  extracted  and  examined  microscopically,  the  doubt 


FILARIA    CONJUNCTIVE 


303 


may  occur  that  one  may  have  mistaken  the  remains  of  the  hyaloid 
artery  for  a  worm,  which  it  resembles  in  form,  size  and  colour  ; 
the  slightest  movement  of  the  eye  also  causes  it  to  move  so  that 
it  simulates  a  living  organism. 

Accordingly  it  would  be  more  correct  to  exclude  all  the  cases  known 
only  ophthalmoscopically  (Quadri,  1857  ;  Fano,  1868  ;  Schoeler,  1875  ;  Evers- 
busch,  1891).  There  then  remains  only  one  positive  case  described  by 
Kiihnt  in  1891.  In  this  case  it  was  possible  to  follow  the  gradual  growth 
of  the  parasite  for  some  time,  and  the  worm,  which  measured  only  0*38 
mm.  in  length,  was  finally  extracted. 

LITERATURE. 

NORDMANN,  A.  v.     Mikrogr.  Beitr.  z.  Naturgesch.  d.  wirbellos.     Thiere,  Berlin,   1832, 

No.  i,  i.,  p.  7  ;    No.  2,  p.  9. 

GESCHEIDT.     Die  Entozoen  d.  Aug.     (Ztschr.  f.  Ophthalm.,  1833,  iii.,  p.  405.) 
KUHNT,  H.      Extr.  in.  neuen    Entozoon  a.  d.  Glaskorp.     (Arch.  f.  Augenheilk,  1891, 

xxiv.,  p.  205.) 
KRAEMER,    A.     Die    thier.    Schmarotz.    d.    Aug.       (Graefe-Saemisch's   Handb.    d.    ges 

Aguenh.,  1899,  Part  II.,  vol.  x.,  chap.  18,  Leipzig.) 


ii.     Filaria  conjunctive,  Addario, 

1885. 

Syn.  :  Filaria  peritonei  hominis, 
Babes,  1880;  Filaria  inermis,  Grassi, 
1887  ')  Filaria  apapillocephala,  Con- 
dorelli-Francaviglia,  1892. 

The  female  only  of  this  species 
is  known.  It  measures  16 — 20 
cm.  in  length  and  0-5  mm.  in 
breadth,  and  is  of  a  whitish  or 
brownish  tint.  The  cuticle  is 
striated  with  the  exception  of 
a  small  field  surrounding  the 
mouth,  which  is  terminal  and 
has  neither  papillae  nor  lips. 
The  oesophagus  measures  o-6 
mm.  in  length  and  is  tooth- 
less. The  anus  is  close  in 
front  of  the  rounded  posterior 
extremity,  and  behind  it  there 


FIG.  20 1. — Filaria  conjunctive?.     To  the 


are  two   (glandular?)  sacs.      The    left-  Resize;    to  the  right,  the  anterior 

.         ,  .  extremity  magnified.     (After  Addario.) 

vulva    is    close    behind    the    oral 

aperture ;     the    vagina    soon    divides    into    two    convoluted    uteri, 

which  are   filled  with  eggs  and  embryos. 


304  THE    ANIMAL   PARASITES   OF   MAN 

This  species  was  first  observed  in  Milan  by  Du-bini  in  the  eye  of  a 
man  ;  subsequently  it  was  observed,  encysted  and  calcified,  by  Babes  in 
the  ligamentum  gastrolienale  of  a  woman  in  Buda  Pest,  and  finally  one 
was  extracted  by  Vadela  from  a  tumour  the  size  of  a  pea  in  the  con- 
junctiva bulbi  of  a  woman  in  Catania  (Sicily),  which  case  has  been 
described  by  Addario.  Possibly  Filaria  palpebralis,  Pace,  1867  (nee  Wilson, 
1844),  which  was  removed  from  a  tumour  of  the  upper  eyelid  of  a  boy, 
belongs  to  this  species ;  probably  Filaria  lentis,  Dies.  (Fil.  oculi  humani, 
v.  Nordm.),  may  also  be  of  the  same  species. 


FIG.  202. — Filaria  conjunctives.  Anterior  end  greatly  magnified  ;  the  mouth 
with  the  pharynx  in  the  middle  ;  in  the  cuticle  on  the  right  side  the  opening  of  the 
vagina  and  behind  it  the  excretory  pore.  (After  Grassi.) 


Filaria   conjunctive   is   certainly   only   an  incidental   parasite   of 

man ;     the    horse    and    ass    are    its    normal  hosts,    but    it    is    not 

common   in   these   animals,  or  is   frequently  confused   with  Filaria 
papillosa,  Rud. 

LITERATURE. 

PACE,  A.     Sopra  un  nuovo  nemat.     (Giorn.  sc.  nat.  ad  econom.,  1867,  n'-) 

BABES,   V.     Ueb.   ein.   neuen   Paras,  d.  Mensch.     (Med.-chir.   Ceiitralbl.,  Wien,  1879, 

xiv.,  p.  554.) 
Ueb.  ein.  im  menschl.   Periton.   gef.   Nemat.     (Arch.   f.  path.  An.,    1880,   Ixxxi., 

p.  158.) 

ADDARIO,  C.     Su  di  un  nemat.  dell'  occhio  umano.     (Ann.  d.  ottalm.,  1885,  xiv-) 
GRASSI,  B.     Filaria  inermis,  ein  Par.  d.  Mensch.,  d.  Pferd.  u.  d.  Esels.     (C.  f.  B.  u. 

P.,  1887,  i.,  p.  617.) 


12.     Filaria    restiformis,    Leidy,    1880. 

This  worm  measures  66  mm.  in  length,  pointed  anteriorly,  the 
posterior  extremity  broadened  and  rounded  off  (1-5  mm.  in  breadth) ; 
the  mouth  is  terminal,  without  lips,  &c.,  the  oesophagus  measures 
i '125  mm.  in  length  ;  the  intestine  appears  to  terminate  blindly. 


FILARIA  :    HOMINISORIS,    LABIALIS,    EQUINA  305 

This  parasite  was  obtained  in  West  Virginia  from  the  urethra  of  a 
young  man,  aged  20,  who  for  a  few  days  previous  to  expelling  the  worm 
passed  cloudy  and  sanguineous  urine.1 


13.     Filaria  hominis  oris,  Leidy,  1850. 

Fourteen  cm.  in  length,  0*16  mm.  in  breadth;  mouth  terminal; 
posterior  extremity  obtuse  and  provided  with  a  recurved  hook. 
The  parasite  was   "  obtained   from   the   mouth  of  a  child."  : 


14,     Filaria  labialis,  Pane,  1864. 

The  parasite  measures  30  mm.  in  length ;  the  anterior  extremity 
is  pointed ;  the  terminal  oral  aperture  is  surrounded  by  four 
papillae  ;  the  anus  opens  0*5  mm.  in  front  of  the  posterior  extremity  ; 
the  vulva  is  2*5  mm.  in  front  of  the  anus  ;  the  uterus  is  double  ;  the 
anterior  one  passes  with  convolutions  forward  to  tjie  cephalic  end  ; 
the  posterior  one  is  directed  backwards  and  remains  rudimentary. 

Extracted  from  a  small  pustule  on   the  inner  surface  of  the  upper  lip.3 

15.     Filaria  equina  (Abildg.),  1789. 

Syn.  :  Gordius  equinus,  Abbild.,  1789  ;  Filaria  equi,  Gmelin,  1789  ; 
Hamularia  lymphatica,  Treutler,  1793  ;  Tentacularia  subcompressa,  Zedder, 
1800;  Fit.  papillosa,  Rud.,  1802;  Fit.  hominis  bronchialis,  Rud.,  1819; 
Filaria  hominis,  Dies.,  1851  ;  Strongylus  bronchialis,  Cobb.,  1879. 

The  body  is  whitish,  filiform,  pointed  posteriorly.  The  cuticle 
presents  a  delicate  transverse  striation.  The  mouth  is  small, 
round,  and  surrounded  by  a  chitinous  ring,  the  border  of  which 
carries,  at  the  sides,  two  semi-lunar  lips,  and  there  is  on  the 
dorsal  as  well  as  on  the  ventral  surface  a  papilliform  process ; 
behind,  corresponding  with  each  submedian  ridge,  is  a  papilla. 
The  male  measures  6 — 8  cm.  in  length,  the  posterior  extremity 
spiral ;  there  are  on  each  side  four  pre-anal  and  four  post-anal 
papillae ;  the  spicules  are  of  unequal  lengths.  The  female  measures 


1  Leidy,  J.,  "On  a  Filaria  reported  to  have  come  from  a  Man  "  (Proc.  A  cad.  Nat» 
Sc.,  Philadelphia,  1880,  p.  130). 

-Leidy,  J.,  "Description  of  Three  Filariae  "  (Proc.  Acad.  Nat.  Sc.,  Philadelphia, 
1850,  v.,  p.  117). 

:'Pane,  "  Nota  su  di  un  elminte  nematoide"  (Annali  dell'  Accad.  degli  aspiranti 
naturalisti,  Napoli,  1864  [3],  iv.). 

20 


306 


THE    ANIMAL    PARASITES    OF    MAN 


9 — 12    cm.    in    length    and    is    viviparous  ;     the    embryos    measure 
0-28  mm.  in  length  and  0*007  mm-  in  breadth. 

Filaria  equina  is  a  frequent  parasite  of  horses  and  asses  ;  it  inhabits 
the  abdominal  cavity  and  from  there  occasionally  invades  the  female  geni- 
talia  or  even  the  liver  ;  it  is  found  more  rarely  in  the  pleural  cavity  or 
in  the  cranium.  The  statement  that  it  also  occurs  in  the  subcutaneous 
connective  tissue  is  probably  due  to  confusion  with  Filaria  h&morrhagica, 
RailL,  1885  (Fil.  multipapillosa,  Cond.  et  Drouilly,  1878).  Finally,  small 
filariae  occur  frequently  in  the  eye  of  the  horse  ;  it  is,  however,  doubtful 
whether  they  belong  to  Filaria  equina. 


Treutler  found  a  filaria  in  the  enlarged  bron- 
chial lymphatic  gland  of  a  patient  suffering  from 
phthisis.  It  measured  26  mm.  in  length  and 
carried  two  small  booklets  (spicules)  at  one  end. 
Blanchard  mentions  another  case  from  Geneva, 


FIG.  204. — Filaria  equina.     Anterior  end,  magnified 
'After    Railliet.) 


tural    size. 
Railliet.) 


Brera    a    third    and   v.    Linstow    a    fourth.      As 
shown  by  the    synonyms  a   few   authors  consider 
this  form  to  be  a  distinct  species,  which  is  hardly 
FiG.203.—Fiiana     probable  ;    others   again   consider   it    to   be   Stron- 

eqmna.  Left,  male  ;       r 

right,  female.  Na-  gylus  apri,  which  is  still  less  likely,  as  the  pos- 
terior extremity  of  male  strongylidae — and  Treutler 
exhibited  a  male  specimen — carries  a  bursa  which 

can    hardly  be    overlooked,    and   which    is    neither    mentioned    nor 

illustrated  by  the  author. 

LITERATURE. 
TREUTLER,    F.    A.     Observ.    patholog.-anat.    auct.    ad    helminthol.    humani    corporis 

continentes.     Lipsiae,  1793. 

BLANCHARD,  R.     Traite  de  Zool.  med.,  1890,  ii.,  p.  16. 

BRERA      Mem.  phys.-med.  sopra  i  princ.  vermi  del  corp.  umano.     Crema,  1811,  p.  31. 
v.  LINSTOW.     Beob.  an  neuen  u.  bek.  Nemathelm.     (Arch.  f.  mikr.  Anat.  u.  Entw., 

I9O2,    lx.,   p.    222.) 

DEUPSER.     Z.  Entw.  d   Fil.  papillosa.     Zool.  Anzg.,  1892,  xv.,  p.  129. 

Exp.  Unters.  iib.  d.  Lebensgesch.  d.  Fil.  pap.     In.-Diss.,  Breslau,  1894. 


FILARIA  :    ROMANORUM-ORIENTALIS,    VOLVULUS  307 

16.     Filaria  ronianorum-orientalis,  Sarcani,  1888. 

Observed  in  the  blood  of  a  Roumanian  woman ;  i  mm.  in 
length,  0'O3  mm.  in  breadth  ;  intestine  and  generative  apparatus 
fully  developed. 

LITERATURE. 
SARCAN,  A.     Fil.  rom. -orient.     (Wien  med.  Presse,  1888,  xxix.,  p.  222.) 

17.     Filaria  volvulus,  R.  Leuckart,  1893. 

The  male  measures  30 — 35,  the  female  60 — 70  mm.  in  length. 
The  parasite  was  first  observed  by  a  German  medical  man  in 
tumours  the  size  of  a  pigeon's  egg,  one  situated  under  the  scalp, 
the  other  on  the  thorax,  of  two  negroes  from  the  Gold  Coast ; 
Leuckart  gave  the  first  description.  Another  case  (Labadie-Lagrave 
and  Deguy)  relates  to  a  French  soldier  who  had  been  in  Tonquin 
for  a  long  time,  and  had  subsequently  accompanied  the  Dahomey 
expedition.  In  this  case  a  young  female  filaria,  measuring  25  mm. 
in  length  and  15  mm.  in  breadth,  was  found  in'  a  lymph  vessel 
within  a  tumour  removed  from  the  shoulder  ;  blood  examinations 
yielded  negative  results.  A  fourth  case  is  mentioned  by  Prout. 

[The  adult  male  measures  30 — 35  mm.  in  length  by  0*14  mm. 
in  breadth.  The  body  is  white,  filiform,  attenuated  at  both  ends. 
The"  head  is  rounded  and  has  a  diameter  of  0*04  mm.  The  cuticle 
is  distinctly  transversely  striated.  The  mouth  is  unarmed.  The 
alimentary  canal  is  straight  and  ends  in  a  subterminal  anus.  The 
tail  is  curved  and  somewhat  flattened  on  the  concave  surface. 
According  to  Brumpt  there  are  three  papillae  on  each  side  of  the 
cloaca  and  three  pairs  of  post-anal  papillae.  Two  unequal  spicules 
may  be  seen  protruding  from  the  cloaca. 

The  adult  female  measures  60 — 70  mm.  in  length  by  0-36  mm. 
in  breadth.  The  head  is  rounded  and  truncated ;  it  measures 
0*04  mm.  in  diameter.  The  tail  is  curved.  The  striations  of  the 
cuticle  are  not  so  distinct  as  in  the  male. 

The  larva  measures  about  300  JJL  in  length  ;  it  has  no  "  sheath." 
The  body  tapers  from  about  the  last  fifth  of  its  length  and 
terminates  in  a  sharply  pointed  tail.  At  about  the  anterior  fifth 
of  the  body  there  is  a  gap  in  the  central  column  of  cells  (Hanson's- 
V  spot). 

Filaria  volvulus  is  found  in  peculiar  subcutaneous  tumours, 
the  size  of  a  pea  to  that  of  a  pigeon's  egg.  The  same  patient 
may  present  one  or  several  of  these  tumours.  -The  regions  of  the 


308  THE  ANIMAL  PARASITES  OF  MAN 

body  most  frequently  affected  are  those  in  which  the  peripheric 
lymphatics  converge.  Thus  they  are  usually  found  in  the  axilla, 
in  the  popliteal  space,  about  the  elbow,  in  the  sub-occipital  region 
and  in  the  intercostal  spaces.  The  tumours  are  never  adherent 
to  the  surrounding  structures,  and  can  be  easily  enucleated.  They 
are  formed  of  a  dense  mass  of  connective  tissue  which  enwraps 
the  parasites  and  encloses  small  cyst-like  spaces  filled  with  a 
greyish  viscous  substance  consisting  almost  entirely  of  filaria 
larvae.  The  position  of  the  adult  worms  within  these  tumours  is 
very  remarkable.  The  greater  length  of  their  coiled-up  bodies 
is  embedded  in  the  connective  stroma,  but  the  posterior  extremity 
of  the  male  with  its  copulating  organs,  and  the  anterior  extremity 
of  the  female  with  its  vaginal  opening,  are  free  in  one  of  the  spaces 
for  the  purpose  of  copulation  and  parturition. 

The  formation  of  the  tumours  is  elucidated  by  Labadie-Lagrave 
and  Deguy's  case.  The  authors  found  an  immature  female  filaria 
volvulus  in  a  lymphatic  vessel  partly  obstructed  by  an  infiltra- 
tion of  fibrin  and  leucocytes.  It  appears  therefore  that  the 
presence  of  the  parasites  within  the  lymphatics  gives  rise  to  an 
inflammatory  process,  and  that  the  consequent  fibrinous  deposit 
envelops  the  parasites,  obliterates  the  lumen  of  the  vessel,  and 
ultimately  isolates  the  affected  tract.  According  to  the  natives, 
the  tumours  may  last  indefinitely  and  never  ulcerate.  Some  old 
patients  told  Brumpt  that  their  tumours  had  been  present  since 
childhood.  Probably  Filaria  volvulus,  like  some  other  filariae,  may 
live  for  many  years. 

Filaria  volvulus  has  been  met  with  in  various  parts  of  West 
Africa.  Leuckart's  cases  occurred  on  the  Gold  Coast.  Prout  saw 
two  cases  in  Sierra  Leone,  Labadie-Lagrave's  case  became  infected 
in  Dahomey.  During  his  travels  through  Central  Africa,  Brumpt 
had  the  opportunity  of  examining  fifteen  cases  on  the  banks  of 
the  Welle  between  Dongon  and  M'Binia.  He  believes  that  in  that 
region  Filaria  volvulus  affects  about  5  per  cent,  of  the  riverine 
population.  Two  other  cases  he  saw  along  the  Itimbri  between 
Bouta  and  Ibembo.  This  filaria  is  also  found  on  the  Kibali  and 
along  several  tributaries  of  the  Welle,  but  appears  to  be  unknown 
on  the  Congo. — L.  W.  S.] 

LITERATURE. 

LEUCKART.     In  Manson,   P.,   Diseases  of  the  Skin  in  Trop.   Clim.     (Andrew  David- 
son's Hyg.  and  Diseases  of  Warm  Countr.,  Edinb.,  Lond.,  1893,  P-  963.) 
LABADIE-LAGRAVE  and  M.  DEGUY.     Un  cas  de  Fil.  volv.     (Arch,  de  paras.,   1899,  ii., 

P-  45I-) 

PROUT,  W.  T.     A  Fil.  found  in  Sierra  Leone.   ?  Fil.  volv.,  Lkt.     (Brit.  Med.  Journ., 
1901,  No.  2091,  p.  209.) 


TRICHOCEPHALUS  TRICHIURUS  309 

1 8.     Filaria  kilimarce,  Kolb,  1898. 

Several  female  specimens  were  once  found  free  in  the  abdomen 
of  a  fallen  Kitu  warrior ;  according  to  Spengel,  who  examined 
them,  the  oral  papillae  of  these  worms  were  similar  to  those  of 
Filaria  medinensis.  Moreover,  Kolb  classifies  together  nematodes 
that  probably  have  no  connection  whatever  with  each  other. 

LITERATURE. 

KOLB,  G.     Die  Filaria  kilimarae  in  Britisch-Ostafrika.     (Arch.  f.  Schiffs.-  u.  Tropen- 
hyg.,   1898,  ii.,  p.  28.) 

19.     Filaria  sp.  ? 

Cholodkowsky  calls  attention  to  filarise  that  are  still  unknown 
which  cause  tumours  resembling  whitlows  on  the  fingers  of  the 
peasants  of  the  Twer  Government. 

LITERATURE. 

CHOLODKOWSKY,  N.  A.     In  Wratsch,  1896,  No.  3. 

Ueb.    einige  selten   b.  Mensch.  vork.  Paras.     (Stzgso.  d.  St.  fetersb.  naturf.  Ges., 
1897,  p.  185.) 

(e)  Fam.   Trichotrachelidce. 
Gen.  6.  Trichocephalus,  Goeze,  1782. 

Syn.  :  Trichiuris,  Roderer,  1761  ;  nee  Trichiurus,  L.,  1758  ;  Mastigodes, 
Zeder,  1803. 

The  anterior  part  of  the  body  is  very  long  and  thread-like  ;  the  pos- 
terior part  sharply  truncated,  is  thickened,  rounded  posteriorly,  and  the 
anus  is  terminal.  The  males  carry  the  posterior  extremity  spirally  rolled 
up  ;  there  is  one  spicule  ;  the  females  have  only  one  ovary  ;  the  vulva 
is  situated  at  the  commencement  of  the  posterior  part  of  the  body  ; 
the  eggs  are  barrel-shaped.  The  trichocephali  live  in  the  large  intestine 
of  mammals,  the  caecum  by  predilection  ;  their  development  is  direct, 
infection  occurs  through  the  ingestion  of  embryo-containing  eggs. 

Trichocephalus  Irichiurus  (L.)  1771. 

Syn.  :  Ascaris  trichiura,  L.,  1771  ;  Trichocephalus  hominis,  Schrank.  1788  ; 
Trichocephalus  dispar,  Rud.,   1801. 

The  male  measures  40 — 45  mm.  in  length,  the  spiculum  is 
2' 5  mm.  long,  and  lies  within  a  retractile  pouch  beset  with  spines. 
The  female  measures  45 — 50  mm.  in  length,  of  which  two-fifths  apper- 
tain to  the  posterior  part  of  the  body.  The  ova  are  barrel-shaped 
and  have  a  thick  brownish  shell  which  is  perforated  at  the  poles. 


3io 


THE    ANIMAL    PARASITES    OF    MAN 


Each  opening  is  closed  by  a  light-coloure^i  plug.  ^ The  eggs  measure 
0*05 — 0*054  mm.  in  length  and  0*023  mm.  in  breadth  ;  they  are 
deposited  before  segmentation.  Trichocephalus  trichiurus  usually 
|  /  lives  in  the  caecum  of  human  beings  and  is  also  occasionally 
found  in  the  vermiform  appendix  and  in  the  "colon,  excep- 
tionally also  in  the  small  intestine  ;  usually  only  a  few  specimens 
are  present,  and  these  do  not  cause  any  particular  disturbances, 
although,  as  Askanazy  found,  they  feed  on  blood  ;  in  other  cases 
cerebral  symptoms  of  more  or  less  severity  are  observed  when 
trichocephali  are  present  in  large  numbers.,  At  post  mortems  per- 
formed soon  after  death  the  filiform  anterior  extremity  of  the 
worm  is  frequently  found  embedded  in  the  mucous  membrane 
(Askanazy). 

The    whip-worm    is    one    of    the    most    common    parasites    of    man    and 

appears  to  be  distributed  over  the  entire 
surface  of  the  globe  ;  it  is,  however, 
more  frequent  in  the  warmer  regions. 
It  is  found  in  persons  of  both  sexes 
and  all  ages  with  the  exception  of 
infants.  In  autopsies  it  is  found  in 
the  following  numbers^  In  Dresden  in 
2-5  per  cent.,  in  Erlangen  in  in  per 
cent.,  in  Kiel  in  31-8  per  cent.,  in 
Munich  in  9-3  per  cent.,  in  St.  Peters- 
burg in  0-18  per  cent.,  in  Gottingen 
in  46-1  per  cent.,  in  Basle  in  23*7  per 
cent.,  in  Greenwich  in  68  per  cent.,  in 
Dublin  in  89  per  cent.,  in  Paris  in 
about  50  per  cent.,  and  in  Southern 
Italy  in  almost  100  per  cent.  On  ex- 
amining the  faeces  the  eggs  of  the 
whip-worm  were  found  as  follows  :  In 
Munich  in  8*26  per  cent.,  in  Kiel  in 
45 -2  per  cent.,  in  Greifswald  in  45  per 
cent.,  in  North  Holland  in  7  per  cent., 
in  Novgorod  in  26-4  per  cent.,  in  St. 
Petersburg  in  5-0  per  cent.,  in  Moscow 
in  5-3  per  cent. 

The  development  of  the  eggs  is  completed  in  water  or  in  moist 
soil,  and  occupies  a  longer  or  shorter  time  according  to  the 
season ;  the  eggs  possess  great  powers  of  resistance,  as  do  the 
larvas,  which,  according  to  Davaine,  may  remain  as  long  as  five 
years  in  the  egg-shell  without  losing  their  vitality.  Leuckart 
proved  by  experiment  that  direct  infection  with  Trichocephalus 
affinis  (ovis  aries)  and  Tr.  crenatus  (Sus  scrofa  dom.)  was  produced 


FIG.  205. — Trichocephalus  tri- 
chiurus. On  the  left  male  ;  on  the 
right  female  with  the  anterior  ex- 
tremity embedded  in  the  mucous 
membrane  of  the  intestine.  Below 
egg. 


TRICHINELLA    SPIRALIS  3! I 

by  embryo-containing  eggs  ;  Railliet  obtained  the  same  results  with 
Tr.  depressiusculus  of  dogs,  and  Grassi  subsequently,  by  means  of 
two  experiments,  demonstrated  the  direct  development  of  Tricho- 
cephalus trichiurus.  In  one  case  embryo-containing  eggs  were 
swallowed  on  June  27,  1884,  and  on  July  24  the  ova  of  tricho- 
cephali  were  found  in  the  faeces  for  the  first  time. 

Trichocephalus  trichiurus  is  found  not  only  in  man,  but  also  in 
various  monkeys  (Tr.  palceformis,  Rud.),  as  well  as  in  lemurs 
(Tr.  lemuris,  Rud.). 

LITERATURE. 

MORGAGNI,    J.    B.      Epist.    anat.,    xviii.,    ad    scripta    pertinentium    eel.    viri    A.    M. 

Valsalvae.      Venetiis,    1740,  ii.,   Ep.   xiv.,  p.  45. 

ROEDERER,   J.  G.     Nachr.  v.  d.  Trichuriden.       (Gott.  gel.  Anz.,    1761,  St.   25.) 
GOEZE.      Vers.   ein.   Naturg.   d.   Eing.-Wurmer,    1782,   p.    182. 
MAYER,  F.   J.  C.      Beitr.  z.  An.  d.  Entoz.,  Bonn,    1841. 
DAVAINE^    Rech.    sur    le    dev.    et    la    propag.    de    1'Asc.    tombr.    et    du    Trich.    de 

I'homme.      (C.  R.  Ac.  sc.,  Paris,   1858,  xlvi.,  p.    1217.) 
EBERTH,    J  .  G.      Beitr.    z.    Anat.    u.    Phys.    d.    Tr.    dispar.      (Z.    f.    w.    Z.    1860,    X., 

pp.    233   and   383,   and    1862,   xi.,   p.   96.) 
LEUCKART,   R       Die  menschl.   Paras.,    1876,   ii.,   p.   492. 

RAILLIET,  A.  •  Notices  Helminthol.  (Bull.  Soc.  centr.  med.  veter.,  1884,  p.  449.) 
GRASSI,  B.  Trichocephalus  u.  Ascarisentwickelung.  (C.  f.  B.  u.  P.,  1887,  i., 

P-    131-) 

WICHMANN.  Ueb.  d.  Verh.  d.  Trich.  zur  Darmschleimhaut.  In.-Diss.  Kiel,  1889. 
MOOSBRUGGER.^  Ueb.  Trichocephaliasis.  (Munch,  med.  Wochenschr.,  1895,  P- 

1097.) 
ASKANAZY,    M.       D.    Peitschenwurm    ein    blutsaug.,    Paras.     (Dtsch.    Arch.    f.    klin. 

Med.,    1896,   Ivii.,   p.    104.) 

Gen.  7.  Trichinella,  Railliet,  1895. 
Syn.  :   Trichina,  Owen,  1835,  nee  Meigen,  1830. 

Very  small  trichotrachelidae,  the  males  of  which  have  no  spicules,  but 
possess  two  conical  appendages  at  the  caudal  extremity  ;  the  females  are 
viviparous  and  possess  one  ovary  ;  the  vulva  is  situated  at  the  border 
of  the  anterior  fifth  of  the  body.  There  is  only  one  species. 

Trichinella  spiralis,  Owen,  1835. 
Syn.  :    Trichina  spiralis,  Owen,  1835. 

The  male  measures  1-4 — r6  mm.  in  length  and  0-04  mm.  in 
diameter.  The  anterior  part  of  the  body  is  narrowed,  the  orifice  of 
the  cloaca  is  terminal  and  lies  between  the  two  caudal  appendages, 
behind  there  are  four  papillae.  The  females  measure  3 — 4  mm. 
in  length  and  0*06  mm.  in  diameter;  anus  terminal. 

Trichinella  spiralis  in  its  aduft  stage  inhabits  the  small 
intestine  of  man  and  of  various  mammals.  It  is  known  to  occur  in 
the  black  rat  (Mus.  rattus),  the  sewer  rat  (M.  decumanus),  the 


312 


THE   ANIMAL  PARASITES   OF  MAN 


domestic  .pig  (Sus  scrofa  dom.),  the  wild  boar  (Sus  scrofa  ferox),  the 
domestic  dog  (Canis  familiaris),  the  fox  (Canis  vulpes),  the  badger 


£ rU  V  \ n  *pWahs'  a>  Mature  female'  "intestinal  trichina"-  E. 
tS?7 •  ;  ^;T  r1  ?"  °Va7s  6'  muture  male'  "intestinal  trichina"  T.' 
testes;  c  New  y-born  larva  ;  d,  larva  of  trichinella  in  the  muscles-^  encap- 
sulated tnchmella  of  the  muscles.  (After  Glaus.)  , 

(Meles  taxus),   the  polecat   (Putorius  fcetidm),   the  marten   (Mustela 
foina),  the  racoon  (Procyon  lotor),  the  Hippopotamus,  and  the  tat ; 


TRICHINELLA    SPIRALIS  313 

trichinellae  have  been  artificially  introduced  into  the  dog,  the  mole 
(Talpa  europcea),  the  mouse  (Mus  musculus),  the  hare  (Lepus 
timidus),  the  rabbit  (Lepus  caniculus),  the  hedge-hog  (Erinaceus 
europaeus),  the  marmot  (Cricetus  vulgaris),  the  sheep,  the  calf,  the 
horse,  &c.  Human  beings  and  the  pig,  rat,  mouse,  guinea-pig  and 
rabbit  are  very  easily  infected  ;  less  easily  the  sheep,  calf  and  horse  ; 
with  more  difficulty  the  cat,  dog  and  badger.  Trichinella  can 
also  be  reared  in  birds  (fowl,  pigeon  and  duck).  However,  the 
young  cannot  be  induced  to  settle  in  the  muscular  system,  but 
are  expelled  with  the  faeces.  By  cold-blooded  animals  as  well  as 
by  insects  (Calliphora  vomitaria)  encysted  trichinellae  are  evacuated 
without  undergoing  any  change,  but  they  will  still  develop  if 
subsequently  ingested,  say,  by  rabbits.  According  to  Gujon,  how- 
ever, trichinella  can  develop  in  salamanders,  because  the  same  has 
found  trichinella  of  the  muscles  in  these  animals,  after  they  had 
been  fed  on  encysted  specimens.  A  high  temperature  (30°  C.) 
must  be  provided  in  which  to  keep  the  experimental  animals 
to  ensure  the  success  of  the  infection. 

History. — Encapsulated  trichinellae  had  already  been  observed  in  London  by 
Peacock  (1828),  and  by  J.  Hilton  (1833),  i*1  tne  muscular  system  of  man  ;  soon 
after  (1835)  Paget  found  them  in  London  in  an  Italian  who  had  died  of 
tuberculosis,  and  recognised  them  to  be  encysted  entozoa,  which  R.  Owen 
described  as  Trichina  spiralis.  Soon  after  some  further  observations  were 
reported  on  the  occurrence  of  encysted  trichinellae  in  man  in  England, 
Berlin,  Heidelberg,  Denmark,  N.  America  ;  they  were  also  found  in  the 
pig  (Leidy,  Philadelphia)  and  the  cat  (Herbst,  Gottingen,  and  Gurlt,  Berlin). 
Herbst  even  succeeded  in  infecting  a  badger  with  encysted  trichinellae  and 
subsequently  infected  two  dogs  with  the  flesh  of  this  badger  (1850).  In 
1855  R.  Leuckart  (Giessen)  also  commenced  feeding  experiments,  and,  like 
Kuchenmeister  and  Virchow  (1859),  first  went  on  the  wrong  track  because 
it  was  believed  at  that  time  that  trichinellae  were  the  larvae  either  of  Tricho- 
cephalus  or  Strongylus.  Nevertheless,  these  experiments  yielded  some  im- 
portant results  ;  they  showed  that  trichinellae  become  adult  in  the  intestine 
within  a  few  days,  and  that  the  females  are  viviparous  (Leuckart). 
Until  that  time  trichinellae  had  been  regarded  as  fairly  harmless  guests 
of  man,  but  opinions  soon  changed  when  Zenker  in  Dresden  (January, 
1860),  in  performing  the  autopsy  of  a  io-y ear-old  girl  who  had  entered 
the  hospital  with  typhoid  symptoms  and  there  died,  found  trichinellae  (not 
yet  encysted)  in  the  muscles  ;  the  intestinal  lesions  characteristic  of 
typhoid  were  lacking,  but  numerous  adult  trichinellae  were  found  in  the 
intestine.  Enquiries  elicited  the  fact  that  at  about  Christmas-time  the 
girl  had  been  taken  ill  after  eating  pork,  and  at  the  same  time  the 
butcher  from  whom  the  meat  was  bought  as  well  as  several  of  his 
customers  fell  sick  ;  the  pickled  pieces  of  the  same  meat  were  fuil  of 
trichinellae.  In  the  face  of  this  information  it  was  not  difficult  to 
ascertain  the  cause  of  the  disease  and  the  manner  of  infection  in 
Zenker's  case,  and  it  was  not  long  before  Leuckart,  Virchow  and  Zenker 


314  THE   ANIMAL  PARASITES   OF    MAN 

were  able  by  renewed  experiments  to  demonstrate  the  cycle  of  develop- 
ment of  Trichinella  spiralis.  Similar  investigations  followed  by  Claus  in 
Wiirzburg,  Davaine  in  Paris,  Fuchs  and  Pagenstecher  in  Heidelberg,  &c., 
&c. 

Hardly  had  Zenker's  case  been  published  than  numerous  observations 
on  trichinosis  in  man  appeared,  some  referring  to  isolated  cases,  others  to 
small  or  great  epidemics,  and  nearly  all  from  North  Germany.  The  worst 
epidemic  was  that  of  Hadersleben  (1865)  in  which  place,  numbering  hardly 
2,000  inhabitants,  337  persons  were  taken  ill  within  a  short  time,  and  of 
these  101  died.  The  source  of  infection  proved  to  be  a  single  pig,  the  flesh 
of  which  had  been  mixed  with  that  of  three  other  pigs  ;  200  of  the  badly- 
infected  persons  had  exclusively  eaten  raw  pork. 

Moreover,  it  soon  became  clear  that  epidemics  of  trichinosis  had  been 
observed  in  Germany  prior  to  1860,  but  that  their  nature  had  not  been 
recognised,  although  in  a  few  cases  trichinellae  had  been  found  in  the 
muscles  of  those  who  had  succumbed. 


HISTORY  OF  THE  DEVELOPMENT  OF  Trichinella  spiralis. 

Shortly  after  their  introduction  into  the  intestine  of  experimental 
animals  the  encysted  trichinellae  escape  from  their  capsules,  which 
are  destroyed  by  the  gastric  juices,  and  they  then  enter  the 
duodenum  and  jejunum,  where  they  become  adult.  During  this 
period  they  do  not  grow  considerably,  the  males  grow  from  o-8— 
ro  mm.  to  1-2 — 1*5  mm.  ;  the  females  to  1*5 — 1'8  mm.  Soon  after 
copulation,  which  already  takes  place  in  the  course  of  two  days, 
the  males  die  off;  the  females,  which  during  the  following  days 
attain  a  length  of  3 — 3 '5  mm.,  either  bore  more  or  less  deeply 
into  the  villi,  or  by  means  of  the  Lieberkiihn's  glands  actually  pene- 
trate into  the  mucous  membrane  (Askanazy,  Cerfontaine,  Geisse), 
and  thus  usually  attain  the  lymphatic  spaces.  A  few  also  pierce 
through  the  intestinal  wall  and  are  found  in  the  mesentery  and 
its  lymphatic  glands.  They  deposit  their  young,  the  number  of 
which,  according  to  Leuckart,  averages  at  least  1,500,  in  the  lymph 
spaces  ;  the  newly-born  larvae  measure  0*09 — o'l  mm.  in  length, 
0*006  mm.  in  diameter  ;  and  they  do  not  appear  to  increase  in 
size  during  their  migrations.  The  migrations  are  mostly  passive, 
that  is  to  say,  the  larvae  are  carried  along  by  the  lymph 
stream  or  by  the  circulating  blood,  but  sometimes  they  are  active, 
as  may  be  inferred  from  the  fact  that  young  trichinellae  are  found 
in  various  parts  of  the  intestinal  wall  beyond  the  chyle  and. lymph 
spaces,  as  well  as  free  in  the  abdominal  cavity. 

The  young  brood  is  distributed  throughout  the  entire  body, 
but  the  conditions  necessary  to  its  further  development  are  found 


TRICHINELLA   SPIRALIS  :     DEVELOPMENT 


315 


only  in  the  transversely  striated  muscular  system ;  the  young 
nematodes  penetrate  the  capillaries,  attain  the  intra-muscular 
connective  tissue  and  then  invade  the  transversely  striated  muscular 
fibres  (Virchow,  Leuckart,  Graham1).  On  the  ninth  or  tenth  day 
after  infection  the  first  trichinellae  have  reached  their  destination  ; 
but  further  invasions  are  constantly  taking  place  because  the 
intestinal  trichinellae  live  from  five  to  seven  weeks  and  continue,  to 
produce  their  young. 


A. 


B. 


FIG.  207. — A.  Isolated  muscular  fibre  of  a  rat,  invaded  by  trichinella, 
510/1.  B.  Section  through  the  muscle  of  a  rat;  the  infected  fibre  has  lost  its 
transverse  striation  ;  its  nuclei  are  enlarged  and  multiplied,  310/1.  C.  Portion  of 
a  trichinella-capsule,  at  the  pole  of  which  connective-tissue  cells  are  penetrating 
the  thickened  sarcolemma.  (After  Hertwig-Graham.) 

The  invasion  of  the  muscles  by  numerous  active  worms  causes  more  or 
less  severe  inflammation  in  man,  which  is  manifested  by  fever,  by  pain 
in  the  muscles,  and  more  particularly  by  muscular  contracture  ;  masticatory, 
respiratory,  and  swallowing  movements  are  rendered  difficult,  and  in  con- 


1  Trichinellce  that  are  unable  to  penetrate  into  muscular  fibres  invariably  die  off, 
no  matter  where  else  they  settle  ;  their  occurrence  in  the  adipose  tissue  is  disputed, 
but  is  still  possibly  correct,  as  bundles  of  muscles  are  present  in  the  fat  of  bacon.  The 
trichinellae  do  not  settle  in  the  myocardium,  although  they  may  reach  it  in  cases  of 
heavy  infection  ;  they  then  die  off  or  wander  into  the  pericardium,  and  eventually  into 
the  cavities  of  the  heart. 


THE    ANIMAL   PARASITES    OF    MAN 


sequence  of  the  pain  they  give  rise  to,  the  patients  avoid  using  the 
voluntary  muscles  as  much  as  possible.  At  the  commencement  of  the 
disease  there  are  more  or  less  severe  attacks  of  diarrhoea,  which,  together 
with  the  fever  and  abdominal  pain  arising  at  this  period,  can  be  ascribed 
to  the  boring  female  trichinellae  and  the  wounds  they  make  in  the  intes- 
tinal wall.  When  the  brood  commences  to  migrate  small  cedemas  appear, 
especially  under  the  eyes. 

The  muscular  fibres  attacked  degenerate,  the  transverse  stria- 
tion  at  first  disappearing ;  the  fibres  then  assume  a  granular 
appearance,  the  nuclei  multiply  and  become  enlarged,  and  are 
surrounded  by  an  area  of  granular  material,  which  stains  more 
deeply  than  the  remaining  contents  of  the  sarcolemma.  Two  or 
three  weeks  after  infection,  the  spirally  rolled-up  trichinellae  have 


V.- 


FIG.  208.  —  Calcified  trichinella  in 
the  muscular  system  of  a  pig  ;  the 
capsules  are  not  calcified.  (After 
Ostertag.) 


FIG.  209. — Various  phases  of  the 
calcification  of  trichinella  of  the 
muscles,  which  starts  at  the  poles 
of  the  capsule. 


grown  to  O'8  —  1*0  mm.,  and  in  their  vicinity  the  muscular 
fibre  is  swollen,  spindle-shaped,  and  the  sarcolemma  is  glassy 
and  thickened.  The  inflammation  also  extends  to  contiguous 
fibres,  especially  to  the  intra-muscular  tissue,  which  prolifer- 
ates greatly,  especially  in  the  vicinity  of  the  degenerated  fyoces. 
While  the  latter  become  more  and  more  absorbed,  the  capsule 
is  formed  by  the  inflamed  connective  tissue,  which,  penetrating 
into  the  glassy  and  thickened  sarcolemma  by  way  of  the  poles  of 
the  spindle,  takes  its  place  and  forms  the  cystic  membrane. 
The  cysts  are  lemon-shaped  and  usually  lie  with  their  longitudinal 
axis  in  the  direction  of  the  muscular  fibres  ;  on  an  average  they 
measure  0^4  mm.  in  length  by  0*25  mm.  in  breadth. 


TRICHINELLA    SPIRALIS  I    DEVELOPMENT  317 

Later  on  adipose  cells  appear  at  their  poles,  and  after  about 
six  or  nine  months  they  commence  to  calcify,  the  process  starting 
at  the  poles  (fig.  209).  Finally,  sometimes  after  the  lapse  of  years, 
the  captive  trichinellae  themselves  become  calcified. 

According  to  experience,  trichinellse  are  not  found  to  be  evenly 
distributed  in  the  muscular  system  of  pigs  ;  the  muscular  parts  of 
the  diaphragm,  the  muscles  of  the  larynx,  tongue,  abdomen  and 
intercostal  spaces  are  their  favourite  positions  ;  this  predilection 
for  the  respiratory  muscles  is  explained  by  their  regular  contrac- 
tions ;  in  addition,  regular  contractions  of  the  capillaries  take 
place  and  favour  the  fixing  of  the  circulating  trichinellae.  The 
same  circumstance  probably  explains  the  frequency  of  the  parasites 
in  the  tongue. 

•  Possibly  also  the  trichinellae  that  bore  direct  through  the 
intestine  may  penetrate  the  muscles  in  the  vicinity  from  the 
abdominal  cavity.  Frequently  also  encysted  trichinellae  are  found 
in  remarkable  numbers  in  the  vicinity  of  the  points  of  insertion  of 
the  tendons,  this  proclivity  being  probably  connected  with  the 
fact  that  the  trichinellse  first  of  all  wander  into  the  muscular 
fibres  and  find  a  natural  barrier  at  the  points  of  insertion  of  the 
tendons. 

The  trichinellae,  in  their  encysted  condition,  remain  alive  and 
capable  of  development  for  many  years.  (In  the  pig  eleven  years 
and  in  man  twenty-five  to  thirty-one  years.)  Encyst ment,  how- 
ever, is  not  a  necessary  condition  for  the  development  of  the 
brood. 

In  consequence  of  the  new  batches  of  young  produced  during  several 
weeks,  the  above-mentioned  symptoms  of  disease  are  often  considerably 
aggravated  ;  the  fever  increases,  delirium  may  arise,  and  infiltration  of  the 
lungs,  fatty  degeneration  of  the  liver  and  inflammation  of  the  kidneys 
may  ensue  ;  the  initial  slight  oedema  may  extend,  the  strength  dwindles, 
and  in  many  cases  the  patients  succumb  to  the  trichinosis.  In  severe 
cases  improvement  of  the  condition  is  only  apt  to  occur  in  the  fourth  or 
fifth  week  ;  the  convalescence  is  always  protracted. 

The  black  rat  and  more  particularly  the  sewer  rat  (Mm 
rattus,  Mus  decumanus1)  are  the  normal  hosts  of  '  Trichinella 
spiralis.  These  animals,  especially  the  last-named  species,2  infect 


1  It  is  still  a  matter  of  dispute  and  can  hardly  be  definitely  settled  whether  trichi- 
nellaa    were    brought    to   Europe    by  the    sewer  rats   which   invaded   Europe    at  the 
end  of  the  eighteenth  century,  or  whether  they  were  imported  with  the  Chinese  pig  in 
1820  or  1830,  when  it  was  introduced  into  England  and  Germany  to  cross  with  the 
native  breeds,  or  whether  finally  trichinellae  are  also  indigenous  to  Europe. 

2  [The  Sewer  Rat  is  M.  decumanus  ;  Mus  rattus  is  the  Black  Rat.— F.V.T.] 


318  THE   ANIMAL    PARASITES    OF   MAN 

themselves  very  easily,  as  they  do  not  spare  the  members  of  their 
own  family,  and  they  also  transmit  trichinosis  to  other  species  by 
which  they  are  devoured,  such  as  pigs,  dogs,  cats,  foxes,  bears 
and  martens.  Man  becomes  infected  with  trichinella  by  eating  the 
flesh,  insufficiently  cooked,  of  infected  pigs,  also,  but  more  rarely, 
by  eating  the  infected  flesh  of  wild  boars,  dogs,  cats,  bears  and  foxes. 

The  infection  of  pigs  may  likewise  take  place  by  their  having  access  to 
the  offal  of  trichinous  pigs  or  being  actually  fed  on  it.  These  are,  how- 
ever, exceptions  which,  as  a  matter  of  course,  are  of  great  importance  in 
certain  places.  As  a  matter  of  fact  the  rats  examined  for  trichinella  were 
always  found  to  be  severely  infected.  Thus  Billings,  in  the  knacker's  yard 
at  Boston,  found  that  76  per  cent,  of  the  rats  were  infected,  and  in  an 
export  slaughter-house  100  per  cent,  were  found  to  harbour  the  parasite  ; 
in  the  City  of  Boston  10  per  cent,  of  the  rats  had  trichinosis.  Heljcr 
found  that  of  704  rats,  from  29  different  places  in  Saxony,  Bavaria, 
Wurtemberg  and  Austria,  8-3  per  cent,  were  infected  with  trichinellae  ;  of 
the  rats  caught  in  the  knacker's  yards  22- 1  were  diseased  ;  of  those  taken 
in  slaughter-houses  2-3  were  infected,  and  of  rats  from  other  localities  only 
0-3  per  cent,  harboured  the  parasite.  Leisering  found  almost  the  same 
figures,  but  in  rats  from  slaughter-houses  5*3  per  cent,  were  infected. 

The  geographical  distribution  of  Trichinella  spiralis  does  not 
correspond  with  the  occurrence  of  trichinosis  in  man  ;  local  customs 
are  an  important  factor,  for  instance,  the  custom  of  eating  pork  in  a 
condition  that  does  not  affect  the  life  of  the  enclosed  trichinella. 
In  places  where  such  customs  do  not  prevail  epidemics  do  not 
occur,  at  the  most  there  are  isolated  cases  of  the  disease,  although 
there  be  a  great  number  of  infected  pigs.  The  following  condi- 
tions prevail  in  North  America  :  In  Boston,  Billings  found  that 
4 — 5'7  per  cent,  of  the  pigs  examined  were  trichinous  ;  Belfield 
and  Atwood  found  that  8  per  cent,  were  infected  in  Chicago. 
Salmon  found  on  an  average  that  2*7  per  cent,  were  infected  (but 
at  various  places  the  percentage  fluctuated  between  0*28 — 16*3 
per  cent.),  yet  epidemics  of  trichinosis  hardly  ever  occur  in  North 
America,  and  only  isolated  cases  of  the  disease  are  met  with  in 
;  German  immigrants,  who  keep  to  their  native  customs. 

This  report,  according  to  the  researches  of  H.  U.  Williams,  must  be 
considerably  modified.  This  author  has  examined  the  muscular  system  of 
human  cadavers  according  to  the  method  employed  by  inspectors  of  meat 
for  pigs.  The  investigations  were  conducted  in  the  Pathological  Institute 
of  the  University  of  Buffalo,  and  the  observer  has  examined  505  bodies 
since  1894,  of  which  27  (=  5-34  per  cent.)  were  invaded  by  trichinella. 
The  cases,  according  to  the  nationality,  are  divided  as  follows  : — 


TRICHINELLA   SPIRALIS  I    DEVELOPMENT 


319 


Trichinella 

Per  cent. 

Examined    ! 

of  Positive 

Absent 

Present 

Results 

Americans  :  — 

(a)  Whites               

207                    201 

6 

2-89 

(6)  Negroes 

70                      65 

5 

7'*4 

British  and  Irish 

62                57 

5 

8-06 

Canadians 

12 

10 

2 

I6'66 

Germans 

49 

43 

6 

12-24 

Italians 

12 

10 

2             !      I6'66 

Other  Nationalities 

27 

27 

O 

0 

Nationality  unknown 

66 

65 

I 

1*51 

Total 

505 

478 

27 

5'34 

It  is  worthy  of  remark  that  half  of  all  the  positive  cases  were  mental 
patients  which  were  found  to  be  affected  with  trichinella  to  well  nigh 
12  per  cent.  Trichinosis  was  not,  however,  the  cause  of  death  in  any 
case.  Very  frequently  the  trichinellae  were  found  calcined  and  dead. 

Conditions  are  similar  in  most  countries  of  Europe,  where,  of 
course,  the  number  of  infected  pigs  is  considerably  smaller,  but 
the  disease  depends  less  on  this  than  on  the  way  in  which  the 
pork  is  prepared. 

Cases  of  trichinosis  have  been  known  to  occur  in  nearly  all 
the  countries  of  Europe  ;  further,  in  Egypt,  Algeria,  East  Africa, 
Syria,  India,  Australia,  and  America.  North  Germany,  more 
especially  the  Saxe-Thuring  States,  is  the  classical  land  for  epidemics 
of  trichinosis,  the  mortality  varies,  but  it  may  be  very  high.1 


Prophylaxis. — The  grave  nature  of  the  disease  and  the  comparatively 
high  mortality  relating  to  trichinosis  led  the  authorities  to  adopt 
certain  preventive  measures,  which  are  the  more  necessary  as  national 


1  For  instance,  extensive  epidemics  occurred  in  Hettstiidt  in  1863  (160  patients, 
28  deaths);  Hanover,  1864-1865  (more  than  300  patients);  Hadersleben,  1865  (337 
patients,  101  deaths);  Potsdam,  1866  (164  patients);  Greifswald,  1866  (140  cases, 
i  death);  Magdeburg,  1866  (240  cases,  16  deaths);  Halberstadt,  1867  (100  cases, 
20  deaths)  ;  Stassfurt,  1869  (over  100  cases)  ;  Wernigerode,  1873  (100  cases,  i  death)  ; 
Chemnitz  (194  cases,  3  deaths)  ;  linden,  1874  (400  cases,  140  deaths)  ;  Niederzwohren, 
near  Cassel,  1877  (half  the  population)  ;  Diedenhofen,  1877  (99  cases,  10  deaths)  ; 
Leipzig,  1877  (134  cases,  2  deaths)  ;  Ernsleben,  1883  (403  cases,  66  deaths);  Strenz- 
Neuendorf,  1884  (86  cases,  12  deaths),  &c.,  &c.  According  to  Johne,  109  epidemics 
with  3,402  cases  and  79  deaths  occurred  in  Saxony  between  1860  and  1889.  Stiles, 
in  a  work  recently  published,  states  that  there  were  8,491  cases  of  trichinosis  with 
513  cases  of  death  (6*04  per  cent.)  in  Germany  from  1860  to  1880;  that  there  were 
6,329  cases  and  318  deaths  (5-02  per  cent.)  between  1881-1898  we  are  well  aware. 
Of  these  latter,  1881-1898,  3,822  (225  deaths)  occurred  in  Prussia,  1,634  (76  deaths) 
in  Saxony,  and  873  (17  deaths)  in  the  remaining  states.  There  is,  however,  no  doubt 
that  many  deaths  from  trichinosis  were  not  recognised,  as  proved  by  experience 
at  post  mortems. 


320  THE   ANIMAL    PARASITES   OF    MAN 

customs  cannot  be  altered  in  a  short  time.  As  the  usual  process  of 
pickling  and  smoking,  even  when  long  continued,  does  not  certainly 
ensure  the  death  of  the  trichinellae  contained  in  the  meat,  and  also 
because  in  roasting  and  boiling  large  pieces  of  pork  a  considerable  time  is 
necessary  to  permit  the  temperature  required  to  kill  off  the  parasites 
(62-70°  C.)  to  penetrate  to  the  middle  of  the  joint,  it  appeared  to  be 
most  practical  to  have  all  pigs  microscopically  examined  for  trichinellae 
before  they,  or  parts  of  them,  were  placed  on  the  market,  and  all  infected 
meat  condemned,  no  matter  whether  the  trichinellae  were  present  in  large 
or  small  numbers,  still  undeveloped  or  calcined.  Since  1877  obligatory 
examination  of  pork  has  been  introduced  in  Prussia,  though  as  yet  it  is 
not  thoroughly  carried  out  ;  other  states  of  North  Germany  as  well  as 
the  larger  towns  of  South  Germany  soon  followed  ;  a  complete  army  of 
trichina  inspectors,  officially  examined  and  periodically  controlled  by  experts, 
and  whose  number  in  Prussia  amounted  to  27,602  in  1896,  and  was  even 
increased  to  28,224  in  1899,  have  the  charge  of  examining  pork  on  certain 
lines  laid  down.  The  orders,  however,  are  by  no  means  narrow.  The 
proceeding  is  usually  that  the  trichina  inspector  himself  goes  to  the 
slaughter-houses,  or  special  samplers  take  pieces  of  the  muscles  that  are 
known  to  be  the  favourite  seats  of  the  parasite  (strips  of  the  diaphragm, 
the  rib  part  of  the  diaphragm,  muscles  of  the  tongue  and  larynx,  inter- 
costal and  abdominal  muscles)  ;  six  small  portions  are  separated  from  each 
piece,  pressed  between  slides  or  special  compressors,  and  carefully  gone 
through  by  examining  them  with  a  microscope  at  low  power.  The  pigs,  free 
from  trichinellae  are  passed  for  commerce  ;  trichinous  pigs,  on  the  other 
hand,  in  Prussia,  are  only  allowed  to  be  used  for  industrial  purposes,  i.e., 
the  hide  and  bristles  are  used,  the  fat  is  allowed  to  be  melted  down,  or 
certain  parts  are  used  for  the  manufacture  of  soap  or  glue.  In  Saxony, 
however,  it  is  still  permitted  to  place  trichinous  flesh  on  the  market,  fully 
declaring  its  nature,  and  after  having  been  heated  to  its  deepest  strata  at 
a  temperature  of  100°  C.  in  a  suitable  apparatus,  and  under  the  supervision 
of  a  veterinary  surgeon. 

As  TO  THE  PROPORTION  OF  TRICHINOUS  PIGS  to  healthy  ones,  the  follow- 
ing tables  give  the  figures  for  Prussia. 

The  proportion,  however,  is  not  only  subject  to  variation  in  separate 
years,  but  differs  according  to  the  district  ;  thus,  in  1884,  in  the  State 
district  of  Minden  there  was  one  trichinous  pig  to  30,146  healthy  animals, 
in  Erfurt  i  :  14,563,  in  the  district  of  Gnesen  i  :  101,  in  Schrimm  i  :  86, 
and  in  Schroda  i  :  68. 

In  Germany  trichinella  is  becoming  LESS  COMMON  in  pigs  (Ostertag). 


(a)  Prussia- 
Pigs  found 

Year.  to  be  Trichinous. 

1878 — 1885   ..    ..    ..    ..    ..  0-061 — 0-048  percent. 

1886 — 1892  ..    ..    ..    ..    ..  0*033 — 0-043 

1896  ..    ..    ..    ..    ..    ..  0-021 

1899  ..    ..    ..    ..    ..    ..  0*014 


TRICHINELLA    SPIRALIS  :    DEVELOPMENT 


321 


Year 

Number  of                                  Number  of 
Pigs  Examined                         Trichinous  Pigs 

Proportion 

1878 

2,524,105                                      1,222 

2065 

1879 

3,164,656 

1,938 

1632 

1881 

3,118,780 

1,695 

1839 

1882 

3,808,142 

1,852 

2056 

1883 

4,248,767 

2,199 

1932 

1884 

4,611,689 

2,624 

1741 

1885 

4,42I,208 

2,387 

1852 

1886 

4,834,898 

2,114 

2287 

1887 

5,486,416 

2,776 

1988 

1888 

6,051,249 

3,in 

1945 

1889 

5,500,678 

3,026 

1818 

1890 

5,590,510 

i,756 

3183 

1891 

6,550,182 

2,187 

2996 

1892 

6,234,559 

2,085 

2992 

1896 

8,759,490 

i,877 

4666 

1899 

9,230,3$3 

1,021 

9040 

(b)  Saxony. 


Number  of  Pigs 
found  to  be  Trichinous. 


Year. 

1891  ..    ..    ..    ..    ..    ..    ..  0-014  per  cent 

1892  ..    ..    ..    ..    ..    ..    ..  o-oii 

1893 0-008 

1894 0-007 

1895  ..      ..      ..      ..      ..      ..      ..  0'012 

1896  ..      ..      ..      ..      ..      ..      ..  0'0102 

1899  .  .     . .     . .     .  .     .  .     . .     .  .  0*004 


(c)  City  of  Berlin. 


Year. 


1883—1893 
1893—1897 


Number  of  Pigs 
found  to  be  Trichinous. 

0-035 — 0*064  per  cent. 

O'O22 O'O28 


There  is  no  doubt  that  the  excellent  preventive  measure  of 
official  inspection  for  trichinella  has  led  to  the  avoidance  of  grave 
disasters  ;  'its  introduction  has  not  yet  caused  an  entire  cessation 
of  trichinosis  in  man,  because  inspection  of  pork  is  not  obligatory 
everywhere,  so  that  human  beings  may  become  infected  by  un- 
examined  trichinous  pigs  from  their  own  country  or  from  abroad, 
and  also  because  an  infection  may  occasionally  escape  notice.  For 
these  reasons  the  meat  imported  into  Berlin  from  abroad  as  free 
from  trichinae  is  examined  again  and  not  always  in  vain  ;  finally, 
also,  gross  negligence  may  at  times  occur,  or  fateful  errors  may 
be  made. 

In  addition  private  prophylaxis  must  riot  be  neglected,  and  its 
chief  aim  should  be  directed  to  the  suitable  preparation  of  pork. 

21 


322  THE   ANIMAL    PARASITES    OF    MAN 

LITERATURE. 

OWEN,  R.     Description  of  a  Microscopic  Entozoon  infesting  the  Muscles  of  the  Human 

Body.     (Transact.  Zool.  Soc.,  London,  1835,  i.,  p.  315,  i  plate.) 
HERBST,  G.     Beobachtungen  iib.  Tr.  spir.     (Getting.   Nachr.,    1851,  p.   260.       Ibid., 

1852,  p.  183.) 

LEUCKART,  R.     Unters  ub.  Tr.  spir.,  i  Edit.,  1860;  2  Edit.,  1866. 
VIRCHOW,  R.     Zur  Trichinenlehre.     (Arch.  f.  path.  Anat.,  1865,  xxxii.,  p.  332.) 
1*1     Darstellung  d.  Lehre  v.  d.  Trichinen.     Berlin,  1864  and  1866. 
ZENKER,   F.   A.     Ueber  die  Trichinenkrankh.   d.   Menschen.     (Virch.    Arch.   f.   path. 
!-i         An.,  1860,  xviii.,  p.  561.) 

Beitr.  z.  Lehre  v.  d.  Trichinenkrankh.     (D.  Arch.  f.  klin.  Med.,  1866,  i.,  p.  90  ; 
M         1871,  viii.,  p.  387.) 

PAGENSTECHER,  H.  A.     Die  Trichinen.    Wiesb.,  1865. 
GOUJON,  L.     Experiences  sur  la  Trich.  spir.     (These,  Paris,  1866.) 
CHATIN,  J.     La  trichine  et  la  trichinose.     Paris,  1883. 

BLANCHARD,    R.     Article  :     Trichine,    trichinose.     (Diet,    encycl.    d.    sc.    med.,    1887, 
f**1         3  Ser.,  xviii.,  Paris.) 
CERFONTAINE,   P.     Contrib.   a  1'etude  de  la  trichinose.     (Arch,   de  biol.,    1893,   xui-» 

p.  125.      Bull.  Ac.  roy.  de  Belg.,  1893  [3].  xxv.,  p.  454.) 
ASKANAZY,  M.     Z.  Lehre  v.  d.  Trichinosis.     (C.  f.  B.  u.  P.,  1894,  xv.,  p.  225.)      Arch. 

f.  path.  An.,  1895,  cxli.,  p.  42.)  ^ 

JOHNE,  A.     Der  Trichinenschauer,  4  Edit.     Berlin,  1893.  ^ll_ 

GEISSE,  A.     Z.  Frage  d.  Trichinenwand.     In.-Diss.,  Kiel,  1894.    *OT 
HERTWIG,  R.     Entw.  d.  Trich.     (Munch,  med.  Wchschr.,  1895,  ^°-  21.) 
EHRHARDT,  O.     Z.  Kenntn.  d.  Muskelverand,  b.  d.  Trich.  d.  Kaninch.     (Beitr.  z.  path. 

An.  u.  z.  allg.  Path.,  1896,  xx.,  p.  i.) 

Z.  Kenntn.  d.  Muskelver.  b.  d.  Trich.  d.  Menschen.     (Ibid.,  p'.  44.) 

GRAHAM,  J.  Y.  Beitr.  z.  Naturg.  d.  Trich.  spir.  (Arch.  f.  mikr.  An.  L.,  1897,  p.  219.) 
BROWN,  T.  R.  Stud,  on  Trichinosis.  (Bull.  Johns  Hopk.  Hosp.,  1897,  viii.,  No.  73.) 
MARK,  E.  L.  Trichinae  in  Swine.  (Twentieth  Ann.  Report  Mass.  State  Board  of 

Health  for  1888,  p.  113.) 
WILLIAMS,  H.  U.     The  Freq.  of  Trich.  in  the  Un.  Stat.     (Journ.  of  Med.  Res.,  1901, 

vi.,  p.  64.) 
STILES,  Ch.  W.     Trichinosis  in  Germany.     (U.S.  Dep.  of  Agric.  Bur.  of  An.  Ind.  Bull., 

1901,  No.  30.,  Washingt.) 
PIRL,  D.     York.  v.  Trich.  i.  Hundefl.  m.  deren  Bedeut.  f.  d.  Fleischbeschau.     (Ztschr. 

f.  Fleisch.  u.  Milchhyg,  1899,  x.,  p.  5.) 


(/)  Fam.  Strongylidcz. 
Gen.  8.  Eustrongylus,  Dies.,  1851. 

Very  large  strongylidae  with  cylindrical  bodies  ;  the  mouth  is  surrounded 
by  six  papillae  ;  the  male  has  one  spicule  and  a  collar-like  bursa.  One  ovary. 
The  vulva  is  in  the  anterior  region  of  the  body. 

Eustrongylus  gigas,  Rudolphi,   1802. 

Syn.  :  Ascaris  canis  et  martis,  Schrank,  1788  ;  Asc.  visceralis  et  renalis, 
Gmelin,  1789  ;  Strongylus  gigas,  Rud.,  1802  ;  Eustrongylus  gigasy  Dies.,  1851  ; 
Strongylus  renalis,  Moq.-Tand.,  1860  ;  Eustr.  visceralis,  Raill.,  1885. 

Colour,  blood-red ;  the  anterior  extremity  somewhat  slender ; 
there  is  a  series  of  about  150  papillae  along  the  lateral  ridges  ;  the 
submedian  ridges  are  strongly  developed,  and  from  them  spring  the 
radiary  muscles  for  the  intestine. 


EUSTRONGYLUS    GIGAS 


323 


The  males  attain  a  length  of  40  cm.,  and  a  diameter  of  4 — 6 
mm.,  the  posterior  extremity  is  transversely  truncated;  the  anal 
orifice  is  within  the  base  of  the  collar-like  bursa,  the  thickened 
edges  of  which  are  beset  with  papillae  ;  the  spicule  measures 
5 — 6  mm.  in  length. 

The  females  attain  a  length  of  100  cm.,  and  a  breadth  of  12 
mm.  The  anus  is  crescent- 
shaped  and  terminal.  The 
vulva  is  50 — 70  mm.  distant 
from  the  anterior  extremity. 
The  eggs  are  oval  and  have  a 
thick  shell  presenting  numerous 
depressions ;  the  shell  itself 
is  brownish,  but  it  Is  colour- 
less at  the  somewhat  thick- 
ened poles  ;  it  measures  0*064 
mm.  in  length  by  0*04  mm. 
in  breadth. 

Eustrongylus  gigas  lives  in 
the  pelvis  of  the  kidney,  more 
rarely  in  the  abdominal  cavity 
of  the  seal,  otter,  dog,  wolf, 
fox,  horse,  marten  and  pole- 
cat, exceptionally  also  in 
human  beings.  Most  of  the 
cases  in  which  this  parasite 
has  been  reported  as  occur- 
ring in  man  may  be  traced 
back  to  unrecognised  Ascaris 
lumbricoides,  or  to  clots  of 
fibrin  ;  twelve  certain  cases, 
however,  remain.  The  case 


FIG.  2i  i.  —  Eggs  of 
Eustrongylus  giga*s, 
above  seen  from  the 
flat,  below  the  opti- 
cal section,  400/1. 
(After  Railliet.) 


recently  described  by  Trumbull  FIG.  2io.—Eustron- 
was  probably  not  a  case  of  g£*  ?&  R™ 
eustrongylus. 

We  are  not  aware  of  .  the  source  of  infection,  but  we  have 
learned  from  Balbiani  that  the  eggs  develop  an  embryo  in  water 
or  moist  soil,  and  that  this  embryo  may  remain  alive  several 
years  without  hatching ;  the  infection  of  dogs  with  embryo-con- 
taining eggs  did  not  succeed ;  an  intermediate  stage  in  fishes  is 
conjectured. 


324  THE    ANIMAL    PARASITES    OF    MAN 


LITERATURE. 

BALBIANI,  G.     Rech.  sur  le  dev.  et  le  mode  de  propagat.  du  Strangle  geant.     (Journ. 

de  1'anat.,  1870,  vii.,  p.  180.    Compt.  rend.  soc.  biol.,  Paris,  1874  [6],  i.,  p.  125.) 
BLANCHARD,  R.     Nouv.  observ.  de  Strongle  geant  chez  1'homme.     (Ibid.,   1886  [8], 

iii.,  p.  379.) 
MAGUEUR.     Strongle  geant  du  rein  expulse  en  partie  par  le  canale  de  1'uretre  chez 

un  enfant  de  deux  ans  et  demi.     (Journ.  med.,  Bordeaux,  1887-88,  p.  337.) 
TRUMBULL,  J.     A  Case  of  Eustrong.  gigas.      (Med.  Record,  1897,  Iii.,  No.  8,  p.  256. 

Ref.  C.  f.  B.  u.  P.,  xxii.,  p.  619.) 
STILES,  Ch.  W.     Notes  on  Paras.  49.     (Ibid.,   1898,  liii.,  No.  14,  p.  469.     Ref.  C.  f. 

B.,  P.  u.  I.,  xxiv.,  p.  505.) 
ROTHSTADT,   J.     Ueb.   d.  York.   v.   Eustr.   gig.  i.   Hund.   d.   Stadt  Warschau.     (Arb. 

zool.  Labor,  d.  Kais.  Univ.  Warschau,  1897,  Russ.) 


Gen.  9.  Strongylus,  O.  F.  Miiller,  1780. 

The  mouth  has  six  small  papillae  ;  the  male  has  a  bursa  copulatrix  and 
two  spicules  ;  the  female  has  two  ovaries,  the  posterior  extremity  is  pointed. 
The  vulva  is  situated  in  the  posterior  half  of  the  body. 


Strongylus  apri,  Gmelin,  1789. 

Syn.  :  Gordius  pulmonalis  apri,  Ebel,  1777  ;  Ascaris  apri,  Gmelin,  1789  ; 
Strongylus  suis,  Rud.,  1809  ;  Strongylus  paradoxus,  Mehlis,  1831  ;  Strongylus 
elongatus,  Duj.,  1845;  Strongylus  longevaginatus,  Dies.,  1851. 

The  male  measures  12 — 25  mm.  in  length  ;  the  bursa  copulatrix 
is  two-lobed  ;  there  are  five  ribs  in  each  lobe  ;  the  spicules  are 
thin  and  about  4  mm.  in  length.  The  females  measure  50  mm. 
in  length,  the  anus  is  close  in  front  of  the  posterior  extremity, 
which  is  recurved  like  a  hook;  the  vulva  is  close  in  front  of  the 
anus.  The  eggs  are  elliptical,  0*05 — 0*1  mm.  in  length,  0*039 — 
0*072  mm.  in  breadth  ;  when  the  eggs  are  deposited  the  embryo 
is  already  formed. 

Strongylus  apri  frequently  lives  in  the  bronchial  tubes — usually 
the  smaller  ones — of  the  pig1  and  wild  boar ;  it  is  also  found  occa- 
sionally in  sheep  and  in  man  ;  in  young  pigs  it  is  apt  to  set  up 
a  bronchitis,  which  frequently  causes  death'. 


1  The  reports  of  the  city  inspection  of  meat  in  Berlin  state  that  Strongylidce  in 
the  lungs  of  pigs  are  by  no  means  rare  ;  therefore,  the  lungs  of  1,941  pig?  were  con- 
demned between  1885-86,  of  1,641  between  1886-7,  of  3,237  between  1887-8,  of  4,855 
between  1888-9,  ol  7>X97  between  1889-90,  and  of  5,574  pigs  between  1890-1,  &c.,  &c. 
Ostertag  found  Strongylus  apri  in  60  per  cent,  of  the  pigs  examined  in  the  Berlin  abat- 
toir;  Meyer  in  Leipzig  found  the  parasite  in  15  per  cent,  of  the  native  pigs  and  in  52 
per  cent,  of  the  Hungarian  pigs. 


STRONGYLUS    APRI 


325 


The  first  communication  as  to  the  occurrence  of  strongylidae  in  ' 
man  was  that  of  Diesing,  who,  in  1845,  in  Klausenburg,  had  the  ( 
opportunity  of  examining 
strongylidae  found  in  the 
lung  of  a  little  boy  six 
years  old  (Strongylus  longe- 
vaginatus,  Dies.)  ;  probably 
also  the  nematodes  found  in 
the  trachea  and  larynx  of 
man,  and  described  by 
Rainey  and  Bristowe  as 
specimens  of  Filaria  trache- 
alis,  belong  to  this  group  ; 
according  to  Chatin  strongy- 
lus  apri  may  also  occur  in 
the  intestine  of  man ;  this 
occurrence,  however,  may  in 
all  probability  have  been  due 
to  an  accidental  introduction 
of  adult  Strongyli  into  the 
intestine,  and  should  not  be 
attributed  to  a  settlement 
from  the  larval  stage. 

The  embryonic  develop- 
ment and  the  larval  stage 
have  been  made  known  by 
Wandolleck.  No  experi- 
ments to  induce  infection 
have  been  made  ;  it  is  pro- 
bable, however,  that  infec- 
tion is  direct  and  without 
the  aid  of  an  intermediary 
host. 


LITERATURE. 


FIG.    212. —  Strongylus    apri.     A.    Posterior 
extremity  of   the  female,  magnified.     B.  Pos- 
terior extremity  of  the  male,  magnified.       C. 
DIESING,   C.  M.     Systema  Helmin-      male  and  female,  natural  size.     (After  Railliet.) 
thum.    Vindob.,  1851,  ii.,  p. 
317.      Revision    der    Nema- 

toden.     (Stzber.  d.  K.  Akad.  Wiss  Wien.  math.-nat.,  1860,  -CL  xlii.,  p.  722.) 
RAINEY.      Entozoon   found  in   the  Larynx.      (Transact.   Path.   Soc.,   London,    1855, 

vi-»   P-    37°0 
CHATIN,   J.     Le  strongle  paradoxal  chez  1'homme.      (Bull.  Acad.  med.,   Paris,    1888, 

No.    15,   p.   483.) 
JELKMANN,    F.      Ueb.    d.    fein.    Bau   v.    Strong,    pulm.    apri   Eb.      In.-Diss.,    Basel. 

(Lpzg.,    1895.) 


326  THE    ANIMAL    PARASITES    OF  MAN 

WANDOLLECK,  B.       Z.    Embryonalentw.    d.   Strong,    paradoxus.      In.-Diss.,    Berlin, 

1891,  and  Arch.  f.  Naturg.,    1892,  Iviii,   p.    123. 
SPEMANN,    H.      Z.    Entw.    d.    Str.    parad.     (Zool.    Jahrb.    An.,    1895,    Part   viii.,    p. 

301.) 


Strongylus.  subtilis,  Looss,  1895. 

The  male  measures  4—5  mm.  in  length  and  anteriorly  measures 
only  0*009  mm-  in  breadth,  whilst  at  the  back,  just  in  front  of  the 
bursa,  it  measures  0-07  mm.  The  muscular  oesophagus  occupies  a 
little  less  than  one-sixth  of  the  body,  and  behind  it  there  are  two 
large  gland  cells  ;  at  the  back  of  these  starts  the  genital  tube 
which  extends  through  the  entire  body  cavity  as  far  as  the  anus. 
The  bursa  consists  of  two  lateral  semicircular  wings,  which 
ventrally  are  connected  by  a  low  cross-bridge  ;  the  ribs  of  the 
bursa  appear  to  be  asymmetrically  arranged,  the  spicules  are  equal 
and  measure  0*15  mm.  in  length,  and  have  irregularly  running 
supports  springing  from  the  anterior ;  between  them  there  is  a 
chitinous  fragment  of  a  boat-like  shape  with  two  fine  points  directed 
ventrally.  The  females  measure  5*6 — 7  mm.  in  length  and  about 
0*09  mm.  in  breadth,  though  the  cephalic  extremity  only  measures 
0*01  mm.  across  ;  the  anus  is  0*097  mm.  in  front  of  the  posterior 
extremity  which  tapers  suddenly  into  a  slender  pointed  tail ;  the 
oesophagus,  intestine  and  glands  are  the  same  as  in  the  male ; 
the  vulva  is  situated  at  the  commencement  of  the  last  fifth  of 
the  body ;  of  the  two  genital  tubes  one  passes  forwards  to  the 
hindmost  cervical  gland,  then  bends  backwards,  and  after  a  short 
run  turns  again  with  its  blind  end  towards  the  front  ;  the 
posterior  tube  runs  as  far  as  the  anus,  then  turns  to  the  front,  and 
shortly  in  front  of  the  middle  of  the  body,  turns  back  again  and 
almost  immediately  terminates  blindly.  The  mature  eggs  are  oval, 
(0*063 — 0*041  mm.)  and  have  thin  shells ;  they  are  apparently 
deposited  before  segmentation. 

This  species  was  found  by  Looss  in  the  anterior  part  of  the 
small  intestine  in  post  mortems  of  fellahs  of  Alexandria  and  Cairo  ; 
it,  however,  also  inhabits  the  intestine  of  the  camel. 

According  to  Ijima  the  same  species  was  found  in  the  stomach 
of  a  Japanese  woman. 

LITERATURE. 

Looss,  A.      Strongylus  subtilis  n.  sp.,  ein  bisher   unbekannter   Parasit  des  Mensch 

i.  Aeg.      (C.  f.   B.   u.   P.,    1895   [i],  xviii.,  p.    161.) 
Notiz  z.  Helm.  Aegypts.  i.      (Ibid.,  xx.,  1896,  p.   864.) 
IJIMA,   J.      Strong,  subt.  in  Japan.      (Zool.  magaz.,   1896,  vii.,  p.   155.) 


ANKYLOSTOMA    DUODENALE  327 

Gen.   10.  Ankylostoma,  Dubini,    1843. 
Syn.  :  Dochmius,  Duj.,  1845. 

Characterised  by  the  dorsally  directed  abrupt  truncation  of  the  anterior 
extremity  within  which  is  the  large  oral  capsule ;  the  oral  aperture  is  round 
and  contains  two  recurved  chitinous  teeth^at  each  side  of  the  median  line 
on  the  ventral  border,  but  only  one_  dorsal  tooth.  In  the  base  of  the 
oral  capsule  there  are  two  chitinous  supports  on  the  ventral  side  and  one 
tooth  on  the  dorsal  side.  The  bursa  is  three-lobed,  and  is  broader  than 
it  is  long  ;  there  are  two  spicules  ;  the  vulva  is  behind  the  middle  ofj  the 
body.1 

ij§^j[Ankylostoma  duodenale,  Dubini,  1843. 

Syn.  :  Strongylus  quadridentatus ,  v.  Sieb.,  1851  ;  Dochmius  anchylostomum , 
Molin,  1860  ;  Sclerostoma  duodenale,  Cobb.,  1864;  Str.  duodenalis,  Schneid. , 
1866  ;  Dochmius  duodenalis,  Lckt.,  1876. 

The  body  is  cylindrical ;  attenuated  anteriorly,  and  of  a  light 
reddish  colour.  In  the  oral  cavity  on  the  ventral  surface  close 
behind  the  orifice  (fig.  214)  there  are  four  hook-like  teeth  directed 
backwards ;  on  the  dorsal  surface  there  are  two  teeth  directed 
forwards ;  in  the  base  of  the  oral  cavity  there  is  one  tooth 
directed  forward  on  the  dorsal  surface  and  two  chitinous  lamellae 
spreading  out  leaf  like  on  the  ventral  surface.  The  males  measure 
8 — 10  mm.  in  length,  0*4 — 0*5  mm.  in  breadth  ;  the  bursa  has  two 
large  lateral  and  one  small  dorsal  alar  processes  ;  the  rib  of  the 
latter  terminates  into  two  tridentate  points  ;  a  curved  rib  directed 
backwards  arises  from  each  side  of  the  trunk  of  the  central  rib  ; 
each  lateral  wing  is  supported  by  four  ribs  ;  the  two  spicules  are 
long  and  slender.  The  females  measure  12 — 18  mm.  in  length, 
the  caudal  extremity  has  a  small  spine ;  the  vulva  is  somewhat 
in  front  of  the  posterior  quarter  of  the  body.  The  eggs  are 
elliptical  and  have  thin  shells,  they  measure  0-055 — 0*065  mm-  m 
length  and  0*032 — 0*045  in  breadth,  and  are  laid  in  a  state  of 
segmentation. 

Ankylostoma  duodenale  lives  in  the  duodenum,  more  rarely  in 
the  first  part  of  the  jejunum  ;  it  is  parasitical  in  human  beings 
and  in  a  few  anthropomorphous  apes ;  it  appears  to  be  distributed 
over  all  the  peopled  parts  of  the  earth;  it  is  very  common 
in  the  warmer  regions,  and  occurs  also  in  the  colder  temperate 
zones  ;  it  is  certainly  not  absent  from  Germany. 


1  Looss,  A.,   "  Ueb.  d.  Giltigk.  d.  Gattungsnamens  Ancylostomum  Dub."  (C.  f.  B., 
P.  u.  I.  (i),  Orig.,  1902,  xxxi.,  p.  422). 


328 


THE    ANIMAL  PARASITES   OF   MAN 


This    parasite  was    discovered    by    Dubini    in    Italy    in    1843,    and    soon 
gained     notoriety    from     the    fact    that     Griesinger   was    able  to   prove    that 

Ankyiostoma  was  the  sole 
cause  of  "  Egyptian  chlo- 
rosis." According  to  Bilharz 
it  is  almost  always  present 
at  post  mortems  in  Egypt.1 
The  disease  caused  by  this 
worm  is  termed  "  mal-coeur  " 
in  the  Antilles,  "  tun- tun  " 
in  Columbia,  "  opila9ao,"  or 
intertropical  hypohaemia,  in 
Brazil.  The  disease  is  due 
to  the  manner  of  nutrition 
of  the  parasites  because  these 
worms  suck  blood  with  their 
head  always  sunk  more  or 
less  deeply  into  the  mucous 
membrane  of  the  intestine  ; 
they  constantly  leave  the 
spots  they  have  attacked,  so 
that  secondary  haemorrhages 
occur ;  in  addition,  the  con- 
dition of  the  diseased  intes- 
tine has  some  effect  on  the 
nutrition  of  the  patients  ; 
perhaps  also  there  are  some 
toxins  produced  by  the  para- 
site itself,  so  that  in  cases 
of  long  standing  the  condi- 
tion of  the  patient  becomes 
serious. 

Ankyiostoma  gained  further 
notoriety  when,  during  the 
construction  of  the  tunnel  of 
St.  Gotthard,  it  was  proved 
to  be  the  cause  of  the  "tunnel 
disease  "  prevalent  amongst 
the  labourers,  and  when  later 
on  it  was  found  to  be  the 

cause  of  the  disease  of  miners 
FIG.    213. — Ankyiostoma   duodenale.      The   male,  .  . 

to  the  left,  magnified  ;  to  the  right  in  its  natural  size.    and  pitmen.     Brickmakers  are 
(After  Schulthess.)  also  sometimes  attacked  by  a 


1  According  to  Looss  (Dist.  heterophyes  u  Dist.  frat.,  1894,  p.  3),  during  1892  it  was 
found  necessary  to  refuse  applicants  for  official  positions  in  consequence  of  excessive 
anaemia,  caused  by  Ankyiostoma,  in  the  following  proportions  :  In  Upper  Egypt, 
3-3  per  cent.  ;  in  Lower  Egypt,  6'2  per  cent.,  and  in  Menonfieh  the  large  proportion 
of  13*9  per  cent.  The  disease,  indeed,  was  already  known  to  the  ancient  Egyptians. 
They  called  it  dad,  or  uha,  and  the  worm  that  caused  it  was  termed  Heltu. 
(R.  Blanchard.) 


ANKYLOSTOMA    DUODENALE  329 

similar  disease  (anaemia),  and  ankylostoma  has  likewise  been  demonstrated 
to  be  the  cause  of  this  disorder.  For  the  last  twenty  years  the  parasite 
has  been  frequently  observed  in  Germany  in  brickmakers  as  well  as  in 
miners  ;  it  has  principally  been  imported  by  Italians  labouring  in  brick 
works  or  mines  ;  but  it  also  occurs  amongst  German  labourers.  It  has 
appeared  most  frequently  in  brick-fields  in  Bonn,  and  Cologne  ;  cases, 
moreover,  are  known  from  the  neighbourhoods  of  Wiirzburg,  Cohsen, 
Sollingen  (near  Rastatt),  and  Berlin.  Amongst  mining  districts  the  Ruhr 
region  is  most  particularly  liable  ;  as  an  example,  during  a  period  of  one 
year  and  nine  months  215  cases  came  under  observation  in  the  Elisabeth 
Hospital  in  Bochum.  Similar  conditions  prevail  in  Austria  and  Hungary 
(Kremnitz,  Schemnitz,  Funfkirchen,  &c.).  Belgium  and  France  have  likewise 
yielded  cases,  and  in  Italy  the  worm  appears  to  be  distributed  to  a  fairly 
equal  (and  frequent)  degree. 

Development. — The  thin-shelled  eggs  are  deposited  in  a  state  of 
segmentation   and   reach   the   open  with   the  faeces  ;    if  the   atmos- 


FIG.    214.  —  Cephalic  extremity  of  ,     .    ,    ,    . 

Ankylostoma    duodenale,   with  the  oral  *">•  72I5-  ~  Ovum  of  Ankylostoma 

capsule.     (Magnified.)  duodenale.     (After  Parona  and  Grassi.)! 

pheric  temperature  is  sufficiently  high  (20—25°  C.),  they  develop, 
preferably  within  the  excrement  (but  never  in  pure  water),  into  a 
rhabditiform  larva  measuring  0*21  mm.  in  length,  which  under 
certain  conditions  may  hatch  out  at  the  end  of  the  first  day, 
and  at -any  rate  always  in  the  course  of  the  second  or  third  day.1 
The  larvae  in  a  few  days  grow  to  0-56—0-6  mm.  and  moult  ; 
soon  a  second  moult  takes  place,  during  which  the  oesophagus 
changes.  Nevertheless  the  creatures  do  not  slip  out  of  their  old 
larval  integument.  They  remain  actively  motile,  and  now  are  no 
longer  sensitive  to  water,  in  which  they  may  be  kept  alive  for 
three  months  ;  they  can  also  withstand  a  certain  degree  of 
desiccation. 

1  The  development  also  depends  on  the  concentration  and  condition  of  the  faeces  ; 
many  eggs  soon  die  off  in  fluid  and  malodorous  faeces  ;    the  addition  of  a  1 
retards  the  development,  as  does  the  lack  of  oxygen  and  lowering  of  the  temperati 
The  ova  die  without  exception  after  twenty-four  to  forty-eight  hours  at  i    U 


330 


THE  ANIMAL   PARASITES   OF   MAN 


Leichtenstern   conducted   unimpeachable  experiments  on  human 
beings,  which  proved  that  infection  takes  place  through  the  direct 

introduction  of  these 
larvae.  When  the  cir- 
cumstances under  which 
miners  and  brickmakers 
work  are  taken  into  con- 
/•\V ;  sideration  the  frequency 

of  the  infection  is  easily 
understood,  and  as  in 
above  -  ground  occupa- 
tions the  ova,  and,  of 
course,  also  the  larvae, 
perish  during  winter 
from  the  effects  of  the 
cold,  conditions  are  far 
more  favourable  to  the 
worm  in  the  deeper, 
and  therefore  warmer, 
mines.1 

Looss,  who  succeeded 
in  infecting  young  cats 
and  dogs,  studied  the 
metamorphosis  which 
the  larvae  go  through 
within  their  host  (fig. 
216)  ;  it  is  completed 
in  three  stages.  The 
larvae  pass  through  the 
stomach  of  the  exper- 
imental animals  com- 
paratively quickly,  yet 
hardly  grow  any  longer 
during  the  first  days  ; 
on  about  the  fifth  day 
the  signs  of  a  future 
moult  become  appa- 


FIG.  2 1 6. — Ankylostoma  duodenale.  On  the  left, 
four  days  after  transmission  into  the  dog  190/1  ; 
in  the  middle  at  the  commencement  of  •  the 
second  stage  of  development  (five  to  six  days), 
105/1  ;  on  the  right  fourteen  to  fifteen  days  after 
infection,  42/1.  (After  Looss.) 


1  There  is  no  relation  at  all  between  the  Ankylostoma  duodenale  and  horses,  such  as 
Rathonyi  strives  to  prove  (Dtsch.  Med.  Wchschr.,  1896,  No.  41),  the  author  is  the  victim 
of  an  error  ;  the  supposed  ova  and  larvae  of  Ankylostomum,  which  he  found  or  culti- 
vated in  the  excrement  of  horses,  originated  from  Sclerostomum  tetracanthum  and 
Scl.  equinum  (Railliet,  A.,  in  C.  R.  soc.  bioL,  Paris,  1897  [10],  iii.,  p.  1132  ;  Ratz,  St., 
v.  in  C.  f.  B.  P.  u  I.,  1898  [i],  xxiv.,  p.  298.) 


UNCINARIA    AMERICANA  331 

rent ;  this'occurs  on  the  seventh  day,  when  the  animals  are  provided 
with  a  provisional  oral  capsule  which  was  not  present  previously.  At 
the  end  of  this  second  period  the  definitive  oral  capsule  with  the 
chitinous  teeth  is  formed,  and  alterations  in  the  position  of  the 
genital  glands,  in  the  intestine,  &c.,  set  in,  and  on  the  completion 
of  the  second  ecdysis,  which  takes  place  on  the  fourteenth  or 
fifteenth  day,  the  worms  have  attained  their  definitive  organisa- 
tion. Their  length  then  averages  1*9  mm.  (male)  and  2-o  mm. 
(female) ;  three  weeks  after  infection,  however,  the  males  in  the 
dog  have  already  attained  a  length  of  8  mm.,  and  therefore  we 
may  conclude  that  maturity  is  attained  in  about  four  or  five 
weeks. 

Recently  Looss  has  discovered  a  second  means  of  entrance  of  larvae  of 
Ankylostoma  in  the  human  body,  which  is  THROUGH  THE  SKIN  ;  the  larvae 
placed  on  the  skin  with  a  drop  of  water  penetrate  the  hair  follicles  in  a 
short  time,  andj  leaving  these  in  the  vicinity  of  the  hair  papillae  thus 
attain  the  corium.-  The  author  concludes  that  the  larvae  then  find  their 
way  into  the  lumen  of  the  intestine,  and  is  of  opinion  that  this  mode  of 
infection — at  all  events  as  regards  the  fellahs — has  a  far  greater  importance 
than  the  infection  per  os.  We  must,  however,  await  the  proofs  of  this 
statement, 


Uncinaria  (=Anchylostoma)  Americana,  Stiles,  1902. 

[In  May,  1902,  Dr.  Stiles  discovered  that  uncinariosis  in  America 
was  not,  as  a  rule,  due  to  the  old  world  hook-worm,  Uncinaria 
duodenalis,  but  to  a  new  species  which  he  named  Uncinaria 
Americana. 

Uncinaria  Americana  can  be  readily  distinguished  from  Uncinaria 
duodenalis.  It  is  shorter  and  more  slender.  The  male  worm 
measures  from  7  to  9  mm.  in  length  by  0-3  to  0-35  mm.  in  diameter ; 
the  female  9 — n  mm.  in  length  by  0-4 — 0-45  mm.  in  diameter. 
The  buccal  capsule  is  much  smaller  ;  and  presents  an  irregular 
border ;  instead  of  four  ventral  hook-like  teeth,  it  is  provided 
with  a  ventral  pair  of  prominent  semilunar  plates  similar  to  those 
of  the  dog  hook-worm,  Uncinaria  stenocephala  ,  the  pair  of  dorsal 
teeth  is  likewise  represented  by  a  pair  of  slightly  developed 
chitinous  plates  of  the  same  nature.  The  outlet  of  the  dorsal 
head-gland,  usually  called  dorsal  rib  or  dorsal  tooth,  projects 
prominently  into  the  oral  cavity.  Deep  in  the  buccal  capsule  are 
one  pair  of  dorsal  and  one  pair  of  ventral  submedian  lancets. 

The  caudal  bursa  of  the  male  presents  a  short  dorso-median 
lobe,  which  often  appears  as  if  it  were  divided  into  two  lobes. 


332  THE    ANIMAL.  PARASITES   OF    MAN 

The  dorsal  ray  is  divided  to  its  base,  its  two  branches  are 
prominently  divergent  and  their  tips  are  bipartite  instead  of 
tridigitate  as  in  U.  duodenalis.  The  common  base  of  the  dorsal 
and  dorso-lateral  rays  is  very  short. 

In  the  female  the  vulva  is  in  the  anterior  part  of  the  body, 
but  near  the  equator. 

The  eggs  are  larger  than  in  U.  duodenalis,  they  measure 
64 — 75  fju  in  length  by  36 — 40  /*  in  breadth. 

So  far,  Uncinaria  ' 'Americana  has  been  found  only  Jn  man,  its 
anatomical  habitat  is  the  small  intestine.  Its  distribution,  so  far 
as  determined,  includes  Virginia,  North  and  South  Carolina,  Georgia, 
Florida,  Alabama,  Texas,  Porto  Rico,  Cuba  and  Brazil. 

The  life  history  of  U.  Americana  has  not  yet  been  investigated, 
but  there  is  no  reason  for  assuming  that  it  will  differ  radically 
from  that  of  U.  duodenalis. — L.  W.  S.] 

LITERATURE. 

DUBINI,  A.     Nuov.  verm.  int.  umano.     (Ann.  univ.  med.  d'Omodei.,  1843,  cvi.,  p.  5.) 
SIEBOLD,  C.  Th.  v.     Ein  Beitr.  z.  Helminthogr.  hum.     (Z.  f.  w.  Z.,  1852,  iv.,  p.    55.) 
GRIESINGER.       Klin.  u.  an.  Beob.  iib.  d.   Krankh.  v.  Aeg.       (Arch.  f.  phys.,  Hlkde., 

1854,   xiii.,   p.    55.) 
PARONA,    C.,    and    GRASSI,    B.     Sull.    svil.    dell'    Anchil.    duod.     (Atti    soc.    ital.    sc. 

nat.,    1878,  xxi.,  p.   53.) 
PERRONCITO,   E.      Helm.    Beob.       (Molleschotts  Unters.   z.    Naturl.   d.   Mensch.,   xii., 

P-    532.) 
BUGNION,   E.      L'ankylost.   duod.   et   1'anemie  du  St.   Gotthard.     (Rev.   med.   Suisse 

romande,   Geneve,    1881,   Nos.    5   and  7.) 

SCHULTHESS,  W.  Beitr.  z.  An.  v.  Anc.  duod.  (Z.  f.  \v.  Z.,  1882,  xxxvii.,  p.  163. 
MENCHE.  Anchyl.  duod.  b.  d.  Ziegelbrenner- Anaemic  i.  Dtschld.  (Ctrlbl.  f.  klin. 

Med.,    1882,  p.    161,  and  Ztschr.  f.  klin.  Med.,   1883,  vi.,  p.    161.) 
PERRONCITO,   E.      L'anem.   d.   mineurs  au  point  de  vue  parasitol.      (Arch.  ital.   de 

biol.,    1882,  ii.,  p.   315  ;     1883,  iii.,  p.  7.) 
GRASSI,    B.      Anchilostomi   ed   Anguillule.       (Gaz.    d.    ospit.,    1882,    No.    41  ;     Giorn. 

R.   Ace.   med.   Torino,     1883,   xxxi.,   p.    119.) 
LUTZ,    A.      Ueb.    Anc.    duod.       (Volkmann's   Sammlg.    kl.    Vortr.,    1888,    Nos.    255, 

256  and  265.) 
LEICHTENSTERN,    O.      Ueb.    Ancyl.    duod.    b.    d.    Ziegelarb.    i.    d.    Umgeb.    Coins 

(Dtsch.  med.  Wchsch.,    1885,  xii.,  Nos.   28-30.    Weit.   Beitr.  z.  Ancylostomen. 

frage.      (Ibid.,    1886,  xii.,  Nos.    11—14.) 

Fiitterungsvers.   mit  Ancyl. -Larven.       (Ctrlbl.   f.   klin.   Med.,    1886,  No.    39.) 
Einig.   iiber  Anc.   duod.       (Ibid.,    1887,   xiii.,   Nos.   26 — 32.) 
CHIARI,  H.      Ueb.  einen  in  Prag  secirt.  Fall  v.  Ancylostomiasis  bei  einem  Kruneger 

(Prag.   med.  Wchschr.,    1893,  No.  44.) 
Looss,  A.      Not.  z.  Helm.  Aeg.  i.     (C.  f.  B.,  P.  u.  I.   1896  [i],  xx.,  p.   865.     ii.     Ibid., 

1897,   xxi.,  p.   913.) 

Z.   Lebensgesch.   d.   Ancyl.   duod.       (Ibid.,    1898,  xxiv.,  p.   484.) 
ZINN,  W.,   and  M.   JACOBY.      Ancyl.   duod.,  Lpzg.,    1898. 
Looss,  A.      Ueb.  d.   Eindr.  d.  Ancyl.-Larv.  in  d.  menschl.,  Haut.     (C.  f.   B.,  P.   u. 

I.  1901  [i],   xxix.,   p.   733.) 
STILES,  CH.  WARDELL.     Report  upon  the  prevalence  and  geographical  distribution  of 

Hook-worm  disease  in  the  United  States.     Washington,  1903.: 

Gen.  ii.  Physaloptera,  Rud.,  1819. 

Mouth  surrounded  by  two  even  lips  usually  situated  at  the  sides,  and 
each  provided  with  three  papillae  and  teeth.  The  posterior  extremity  of 


ASCARIS    LUMBRICOIDES  333 

the  male  is  lancet-shaped,  in  consequence  of  an  expansion  of  the  cuticle, 
with  four  pairs  of  pedunculated  external  papillae  and  a  number  of  unpe- 
dunculated  inner  papillae  ;  the  spicules  are  unequal  ;  the  female  has  two 
ovaries ;  vulva  in  the  anterior  region  of  the  body.  It  lives  in  the  intestine, 
and  more  especially  in  the  stomach,  of  carnivorous  mammals,  birds  and 
reptiles. 

Physaloptera  caucasica,  v.  Linstow,   1902. 

The  male  measures  14*2  mm.  in  length  and  0*71  mm.  in 
breadth  ;  the  bursa  is  broad,  rounded  off  in  front  and  narrower  at 
the  back,  the  right  spicule  measures  0*62  mm.  in  length,  the 
left  spicule  1*76  mm.  ;  there  are  two  unpedunculated  papillae  in 
front  of  the  orifice  of  the  cloaca,  four  behind  it  and  six  at  the 
tail.  The  female  measures  27  mm.  in  length,  1-14  mm.  in  breadth  ; 
the  caudal  extremity  is  rounded  off  ;  the  vulva  is  on  the  border  of 
the  first  and  second  sixth  of  the  length  of  the  body ;  the  eggs  have 
thick  shells,  and  measure  0*057 — °'°39  mm.  It  has  hitherto  only 
been  observed  once:  by  Menetries  in  the  intestine  of  man  (Caucasus). 


(g)  Fam.  Ascaridce. 
Gen.  12.  Ascaris,  L.,  1758. 

The  oral  cavity  is  surrounded  by  three  largish  papillae,  of  which  one  is 
in  a  dorsal  position  and  the  other  two  ventral.  The  male  has  two  spicules 
of  equal  length  and  numerous  pre-anal  and  post-anal  papillae.  The  vulva 
lies  in  front  of  the  middle  of  the  body.  All  the  species  probably  develop 
direct  without  an  intermediary  host. 

i.  Ascaris  lumbricoides,-  L.,  1758. 

The  colouring,  in  the  fresh  condition,  is  reddish-yellow  or 
greyish-yellow  ;  the  body  is  of  an  elongated  spindle  shape.  The 
dorsal  oral  papilla  carries  two  papillae  of  sense,  the  two  ventral 
oral  papillae  each  one  papilla  of  sense.  The  male  measures  from 
15 — 17 — 25  cm.  in  length,  and  about  3  mm.  in  diameter ;  the 
posterior  extremity  is  conical  and  bent  hook-like  ventrally  ;  the 
spicules  measure  2  mm.  in  length,  are  curved,  and  somewhat 
broadened  at  their  free  end  ;  on  each  side  around  the  orifice  of 
the  cloaca  there  are  70 — 75  papillae,  of  which  seven  pairs  are  post- 
anal.  The  testicular  tube  is  much  folded  on  itself,  shows  through 
the  body  integument  and  is  about  eight  times  the  length  of  the 

1  Linstow,  v.,  "  Zwei  neiic  Paras,  d.  Mensch."  (C.  f.  B.,  P.  u.  I.  [i],  1902,  xxxi., 
Orig.,  p.  769). 


334 


THE   ANIMAL    PARASITES    OF    MAN 


body.  The  females  measure  20 — 25 — 40  crn.  in  length  and  about 
5  mm.  in  diameter,  the  posterior  extremity  is  conical  and  straight. 
The  vulva  is  at  the  border  between  the  anterior  and  middle  third 
of  the  body  ;  the  two  uterine  tubes  pass  straight  to  the  posterior 
end  of  the  body;  the  convoluted  ovaries  measure  ten  times  the 
length  of  the  body. 

The  ova  are  elliptical  with  a  thick  transparent  shell  (fig.  218), 
and  an  external  coating  of  albumen  which  forms  protuberances  ;  the 
ova  measure  0*05 — 0^07  mm.  in  length,  0^04 — 0*05  mm.  in  breadth ; 
they  are  deposited  before  segmentation  ;  the  albuminous  coating 
is  stained  yellow  by  the  colouring  matter  of  the  faeces. 

Ascaris   lumbricoides   is   one   of   the   most   frequent   parasites    of 


'  FIG.  217. — Ascaris  himbricoides.  a,  posterior 
extremity  of  the  male  with  the  spicules  protruding 
from  the  orifice  of  the  cloaca  (Sp.)  b,  anterior 
extremity  from  the  dorsal  surface.  c,  anterior 
extremity  from  the  ventral  surface.  P.,  porus 
excretorius.  (From  Claus.) 


FIG.  218. — Ovum  of  Ascaris 
lumbricoides,  with  shell  and 
albuminous  envelope.  400/1. 


man  ;  it  is*  distributed  all  over  the  inhabited  parts  of  the  world, 
and  though  it  is  particularly  frequent  in  the  warmer  regions,  yet 
it  also  occurs  in  Finland,  Greenland,  &c.  In  temperate  climates 
Ascaris  lumbricoides  occurs  most  frequently  in  young  children  ;  it  is, 
moreover,  more  common  amongst  country  dwellers  than  amongst 
the  inhabitants  of  towns,  but  is  not  lacking  in  infants,  adults  and 
aged  persons.  As  a  rule  only  a  few  specimens  of  the  ascaris  are 
present  in  the  intestine,  but  many  cases  are  known  in  our  zone 
in  which  several  hundreds  of  worms  have  been  found  in  the  same 
patient.  The  ascaris  is  particularly  numerous  in  the  negroes  of 
Africa  and  America. 

The  parasite  was  already  known  in  ancient  times  ;  the  Greeks 
called  it  eX/ui/9  arpoyyvXrj,  Plinius  termed  it  Tinea  rotunda,  later 
on  it  was  named  Lumbricus  teres  ;  the  da/cap^  of  the  Greeks  is  our 
oxyuris. 


ASCARIS    LUMBRICOIDES 


335 


The  small  intestine  is  the  normal  habitat  of  A  scans  lumbricoides  ;  the 
worms,  however,  often  leave  this  part  of  the  intestine  and  wander  into  the 
stomach,  whence  they  are  frequently  evacuated  by  vomiting,  or  they  may 
creep  through  the  oesophagus  into  the  pharynx  and  crawl  out  through  the 
nose  or  mouth  ;  very  rarely  they  may  find  their  way  into  the  Eustachian  tube 
or  into  the  naso-lachrymal  duct,  or  into  the  excretory  ducts  of  the  liver  and 
pancreas  ;  exceptionally  they  may  gain  the  trachea,  and  they  have  also  been 
found  in  the  abdominal  cavity.  They  may  bore  through  adhesions  between 
the  intestinal  wall  and  the  epigastrium  (worm  abscess)  ;  they  occasionally 
penetrate  the  urinary  apparatus  and  are  passed  with  the  urine  ;  in  feverish 
diseases  Ascaris  lumbricoides  usually  leaves  the  intestine  spontaneously.  It 
is  obvious  that  these  wanderings  may  be  accompanied  by  the  most  serious 
symptoms  ;  but  in  sensitive  persons  the  invasion  of  even  only  a  few 
intestinal  ascarides  gives  rise  to  a  series  of  almost  inexplicable  symptoms 
(hysterical,  epileptiform  attacks,  cerebral  congestion,  aphonia,  &c.),  which 
cease  with  the  expulsion  of  the'  worms,  so  that  many  authors  are  driven 
to  the  conclusion  that  the  ascarides  secrete  a  toxin.  Fortunately,  the 
presence  of  Ascaris  lumbricoides  in  the  intestine  is  easily  demonstrated  by 
the  microscopical  examination  of  the  faeces. 

*~ 

Development. — Sever  il  authors  (Gros,  Schubart,  Richter,  Leuc- 
kart  and  Davaine)  have  demonstrated  that  the  ova  of  ascaris 
develop  in  water  or  moist  earth  after  a  long  period  of  incubation. 
Freezing  and  desiccation  (if  for  not  too  long)  do  not  injure  their 
powers  of  development  ;  the  duration  of  the  development  depends 
on  the  degree  of  the  surrounding  temperature.  At  a  medium 
temperature,  after  the  varying  period  of  incubation,  it  takes  from 
thirty  to  forty  days  for  the  embryo  to  become  formed.  The 
spirally  rolled  up  embryo,  with  its  so-called  "  tooth,"  formed  by 
three  papillae  close  together,  never  leaves  the  egg  -  shell  in  the 
open,  even  if  the  eggs  are  kept  for  years  under  favourable 
conditions.  Davaine  proved  that  the  larvae  hatch  out  in  the 
intestine  of  the  rat  but  are  again  expelled  with  the  faeces  ;  he 
therefore  concluded  that  the  hatching  likewise  takes  place 
within  the  intestine  of  man,  but  is  followed  by  the  settlement 
of  the  larvae.  In  the  meantime  Leuckart  had  sought  to  in- 
fect himself  by  swallowing  embryo-containing  eggs,  but  without 
results,  he  therefore  conjectured  that  there  must  be  an  inter- 
mediary host,  and  v.  Linstow  thought  he  had  found  it  in  myria- 
pods  (Julus  guttulatus).  Subsequently,  Davaine's  opinion  proved 
correct  ;  first  of  all  Grassi  succeeded  in  infecting  himself  by 
swallowing  100  embryo-containing  eggs  of  Ascaris  lumbricoides ; 
_five_  weeks  after  ingestion  the  worms  had  attained  maturity  and 
their  ovaT  appeared  in  the  faeces.  Calandruccio  also  sought  to  infect 
himself,  but  failed,  yet  he~  succeeded  in  infecting  a  little  boy  seven 


33^  THE    ANIMAL    PARASITES    OF    MAN 

years  old.  Lutz  also  reports  a  successful  experiment  which  must  have 
been  positive,  as  the  worms  were  expelled  young.  Finally,  Epstein 
conducted  unimpeachable  experiments  on  three  children,  which  places 
direct  infection  with  embryo-containing  eggs  beyond  doubt ;  he, 
moreover,  proved  that  the  development  of  the  eggs  takes  place  more 
rapidly  in  the  faeces  when  there  is  free  admission  of  air,  sun,  and  a 
sufficiency  of  moisture. 

Accordingly,   infection  occurs    partly  through  water,   but  princi- 
pally direct  from  the  soil. 

LITERATURE. 

CLOQUET,   J.      Anatomie  des  vers  intestinaux.      Paris,   1824. 

CZERMAK,    J.      Bau.     .     .     .     der   Haut   von   Asc.    lumbr.      (Stzb.    K.    Acad.    Wiss. 

math.-nat.  Cl.  Wien.,    1852,  ix.,  p.  755.) 
RHODE,  E.     Beitr.  z.  Kenntn.  d.  Anat.  d.  Nematoden.     (Zool.  Beitr.  [A.  Schneider], 

1883,  i.,  p.    n.) 
BENEDEN,    E.    van.      L'appar.    sex.    fern,    de    1'Asc.    megaloceph.       (Arch,    de    biol., 

1883,  iv.,  p.  95.) 
DAVAINE,  E.      Rech.   sur  le  devel.     .     .     .     de  1'Ascar.  lombr.      (Compt.  rend.  Ac. 

sc.,    Paris,    1858,    xlvi.,   p.    1217.)      (Mem.    soc.    biol.,    Paris,    1862    [3],   iv.,   p. 

261.) 
HALLEZ,    P.       Rech.    sur    1'embryol.    et    sur    les    condit.    du    develop,    de    quelques 

nemat.      Paris,    1885. 
LINSTOW,  v.      Ueber  den  Zwischenwirth  von  Asc.  lumbr.       (Zool.   Anzg.,    1886,  ix., 

P-   525-) 
GRASSI,    B.      Trichocephalus-   und   Ascarisentwickelung.       (C.    f.    B.    u.    P.,    1887,    i., 

p.    131,    1888,   Vol.  in.,   p.   748.) 
LUTZ,    A.      Zur   Frage    der    Invasion   von.     .     .     .     Asc.    lumbr.       (Ibid.,    1887,    ii., 

P.-  7J3-) 

LEUCKART,  R.      Die  Uebergangsweise  der  Asc.  lumbr.       (Ibid.,  p.  718.) 
LUTZ,  A.      Weiteres  zur  Uebertragung  der  Spulw.       (Ibid.,   1888,  iii.,  p.   265.) 
EPSTEIN,   A.      Ueb.  d.   Uebertrag.  d.   menschl.  Spulw.     (Jahrb.   f.   Kdrhlkde.   N.  F., 

1892,  xxxiii.,  No.   3.) 
NASSONOW,    N.  W.      Z.   Anat.    u.    Biol.    d.    Nemat.,    2.      (Arb.    a.    d   Labor,    d.    zool. 

Inst.  d.  Warsch.  Univ.  f.,   1897,  P-   J33-      Warschau,    1898.)     (C.  f.  B.,  P.  u. 

i.  [i],  xxv.,  p.   837.) 

GUIART,   J.      Role  path,   de  1'Asc.   lumbr.       (Arch,  de  parasit.,    1900,  iii.,  p.   70.) 
SICK,  C.      Ueber  Spulwiirmer  in  den  Gallenwegen.      Tubingen     1901. 


2.     Ascaris  canis,  Werner,  1782. 

Syn.  :  Lumbricus  cam's,  Werner,  1782;  Asc.  teres,Goeze,  1782;  Asc.  cati 
et  caniculte,  Schrank,  1788^  Asc.  canis  et  felis,  Gmelin,  1789;  Asc.  tri- 
cuspidata  et  felis,  Bruguiere,  1791  ;  Asc.  werneri,  Rud.,  1793  ;  Fusaria 
mystax,  Zeder,  1800  ;  Asc.  marginata  et  mystax,  Rud.,  1802  ;  Asc.  alata, 
Bellingham,  1839. 

The  anterior  end  is  somewhat  recurvate,  and  provided  with 
lateral  alar  appendages,  which  give  it  the  shape  of  an  arrow-head  ; 
three  almost  equal  lips  around  the  mouth.  The  male  measures 
40 — 60  mm.  in  length,  i  mm.  in  diameter;  the  posterior  end  is 
spirally  bent  and  presents  twenty-six  pairs  of  papillae,  of  which  five 


ASCARIS   CANIS 


337 


are  post-anal.  The  female  measures  120 — 180  mm.  in  length  ;  the 
posterior  end  is  straight  and  somewhat  conical  ;  the  vulva  is  in  the 
middle  of  the  anterior  end  of  the  body.  The  eggs  are  almost 
spherical  with  a  thin  shell  and  an  albuminous  layer  that  is  but 
slightly  protuberant.  They  measure  0*068 — 0-072  mm. 

Ascaris  canis  is  a  very  common  parasite  in  the  intestine  of 
cats  and  dogs,  but  it  also  occurs  in  the  lynx,  lion,  puma,  &c.  ;  it 
has  also  been  observed  in  man  in  about  eight  cases,  four  in  Eng- 


FIG.  219. — Transverse  section  through  the  head  part  of 
Ascaris  canis  from  the  cat,  with  the  pterygoid  prolongations 
of  the  cuticle.  In  addition,  one  may  note  the  four  fields 
of  muscles,  the  longitudinal  ridges  with  the  oesophagus  in 
the  transverse  section  (magnified).  (After  Leuckart.) 


FIG.  220. — Ovum 
of  Ascaris  canis, 
with  thin  albu- 
minous envelope 
(magnified). 


land,  two  in  Germany,  one  in  Denmark  and  one  in  North  America. 
In  two  of  these  cases  the  parasites  were  coughed  up. 

Grassi  is  of  opinion  that  this  species  does  riot  occur  in  man, 
as  he  vainly  sought  for  it  in  over  1,000  persons,  and  experimental 
infections  on  man  yielded  negative  results. 

The  development  of  Ascaris  canis  is  similar  to  that  of  Ascaris  lumbri- 
coides  ;  but  the  eggs,  in  spite  of  the  delicacy  of  their  shells,  have  great  powers 
of  resistance  and  develop  equally  well  in  water  and  damp  earth,  in  a  solution 
of  chromic  acid,  alcohol,  turpentine,  solution  of  soda,  &c.  It  is,  however, 
but  seldom  that  the  embryos  (0*36  mm.  in  length)  hatch  out.  The  trans- 
mission is  direct. 

LITERATURE. 

BELLINGHAM,  O.  B. — Undescrib.  Spec,  of  Human  Intestinal  Worm.  (The  Dublin 
Med.  Press,  1839,  i.,  p.  104;  Gaz.  des  hopitaux,  1839  [2],  i.,  p.  97.) 

COBBOLD,  T.  Sp.  On  the  occurr.  of  Asc.  m.  in  the  Human  Body.  (The  Lancet,  1863, 
i.,  p.  31.) 

MORTON,  F.     Asc.  myst.      (Ibid.,  1865,  i.,  p.  278.) 

LEUCKART,  R.     Menschl.  Parasiten.     (ist  edit.,  ii.,  p.  261.) 

KELLY,  H.  A.     (American  Journ.  of  Med.  Sc.,  1884,  [2]  Ixxxviii.,  p.  483.) 

DAVAINE,  C.  Sur  la  const,  de  1'oeuf  des  cert,  entozoaires.  (Mem.  soc.  biol.,  Paris, 
1862  [3],  iv.,  p.  273). 

HELLER,  C.     Ueb.  Asc.  lumbr.    (Szgsber.  d.  Erlang.  phys.-med.  Societ,  1872,  iv.,  p.  71). 

HERING.  Beitr.  z.  Entw.  einig.  Eing.-Wurm.  (Wiirttemb.  nat.  Jahreshfte,  1873, 
p.  305.) 

•GRASSI,  B.  Beitr.  z.  Kenntn.  des  Entwickelungscyclus  von  5  Paras,  d.  Hundes 
(C.  f.  B.  u.  P.,  1888,  iv.,  p.  609). 

GRASSI.  B.     Intorno  all'  Asc.  myst.     (Gazz.  med.  it.  lomb.,   1879,  xxxix.,  p.  276.) 

22 


338 


THE   ANIMAL    PARASITES    OF    MAN 


3.     Ascaris  maritima,  Leuckart,  1876. 

Only  one  immature   specimen,  a    female   (43  mm.  in  length  and 
I  mm.  in  breadth),  has  hitherto  been  described,  and  it  was  vomited 
by    a    child    in    North    Greenland    in    1865.      (R.    Leuckart,    Die 
menschlichen  Parasiten,  1876,  i.,  edition  ii.,  p.  877.) 
rif 

13.     Gen.    Oxyuris,    Rudolphi, 
1803. 

The  three  labial  papillae  are  only 
slightly  protuberant,  the  oesophagus 
is  long  and  presents  a  distinct  dila- 
tation. The  male  has  one  spicule 
and  two  pairs  of  pre-anal  papilla ;  the 
posterior  end  of  the  female  is  drawn 
out  to  a  point.  The  vulva  is  in  the 
anterior  part  of  the  body. 

Oxyuris  vermicular  is  (Linne), 
1767. 

Syn.  :  A  scar-is  vermicularis,  L. ;  Fu- 
saria  vermicularis,  Zeder,  1803. 

Colour  white,  the  annulated 
cuticle  forms  swellings  at  the 
anterior  end  which  extend  some 
distance  back  along  the  middle 
of  the  ventral  and  dorsal  sur- 
faces ;  the  longitudinal  supports 
of  the  skin  corresponding  to  the 
lateral  ridges  are  much  more  feebly 
developed  ;  there  are  three  small 
retractile  labial  papillae  around 
the  mouth.  The  male  measures 
FIG.  222.— On  the  3 — 5  mm.  in  length,  and  shortens 

left,    female  ;    on    the  j        ,        ,, 

right,   male  ;    greatly    on  death  ;  the  posterior  extremity 
enlarged.     A.,  anus ;    of  the  body  is  rolled  ventrally  and 

M.,  mouth ;  V.,  vulva.  .-  / 

(After  ciaus.)  presents  six  papillae.     The  female 

is  10  mm.  in  length  and  0*6  mm. 

-in  diameter ;  the  anus  is  about  2  mm.  in  front  of  the  tip  of 
the  tail ;  the  vulva  is  in  the  anterior  third  of  the  body ;  the  eggs 
are  oval,  thin-shelled  and  measure  0*05  :  0-016 — 0-02  mm.  ;  they 
are  deposited  with  embryos  already  developed  and  are  very  seldom 
found  in  the  faeces. 


FIG.  221. — A., 
male  ;  and  B., 
female,  of  Oxy- 
uris vermicula- 
ris.  (s/i.) 


OXYURIS    VERMICULARIS  339 

Oxyuris  vermicularis  has  been  known  since  a  remote  period,  and  is  one 
of  the  most  frequent  and  widely-spread  parasites  of  man.  It  occurs 
principally  in  children,  and  lives  in  the  large  intestine.1  The  females  are 
apt,  in  the  evening,  when  the  patients  retire  to  bed,  to  leave  per  anum, 
causing  troublesome  itching,  and  to  wander  between  the  nates  and  peri- 
naeum,  from  whence,  in  girls,  they  occasionally  reach  the  vagina.2  Large 
numbers  may  occasionally  be  harboured  without  inconvenience  ;  in  other 
cases  various  reflex  symptoms  are  set  up  even  in  adults,  which  may  rise 
to  epileptiform  attacks.  Occasionally  the  oxyuris  are  evacuated  by  the 
mouth  ;  it  is  only  very  rarely  that  they  reach  the  urinary  bladder. 

Development. — The  eggs,  which  often  adhere  together,  contain  a 
tadpole-like  embryo,  the  thin  tail  of  which  is  bent  upwards 
ventrally  ;  the  embryo  in  a  short  time,  given  a  sufficiently  high 
temperature,  passes  into  a  second  embryonal  stage,  a  folded  nema- 
tode  shape,  lying  in  the  egg-shell,  either  in  the  faeces,  with  which  also 
numerous  females  pass  out,  or  in  the  moisture  of  the  groove 
between  the  buttocks,  and  they  there  await  the  opportunity  of 
being  reintroduced  into  man  per  os.  It  is  very  improbable  that  the 
settlement  may  also  take  place  direct  in  the  large  intestine,  as  is 
occasionally  stated,  because  although  the  harbourers  of  oxyuris  are 
frequently  liable  to  auto-infection,  this  takes  place  through  the  mouth, 
and  is  conveyed  by  the  fingers,  on  which  the  ova  of  oxyuris,  and 
occasionally  the  female  worms  have  clung. 

The  opportunity  for  this  is  afforded  every  evening,  as  naturally  the 
troublesome  itching  caused  by  the  travels  of  Oxyuris  vermicularis  is  met 
by  scratching  and  rubbing  with  the  fingers.  It  is,  therefore,  possible  that 
the  eggs  may  even  thus  be  introduced  into  the  nose,  where  the  young  oxyuris 
are  perhaps  hatched  out,  if  they  get  high  enough  up  on  the  moist  pituitary 
mucous  membrane.  As  a  matter  of  fact  the  larvae  of  oxyuris  have  been 
found  in  the  nose.  Moreover,  it  may  be  understood  that  the  eggs  of  Oxyuris 
are  transferred  from  person  to  person  by  the  hand,  directly  or  indirectly. 
This  again  explains  the  wholesale  infections  which  occur  in  collective 
dwellings,  after  a  person  harbouring  oxyuris  has  been  admitted  into 
boarding  houses,  &c.  The  primary  infection  may  be  also  caused  in  other 

ways by  foods,  fruits,  vegetables  and  other  articles  that  are  eaten  raw,  and 

are  polluted  with  the  ova   of  oxyuris.     Perhaps   also  flies  or  their  excrement 


1  It  has  recently  been  stated  that  the  lower  part  of  the  intestine  is  the  original 
seat  of  the  Oxyuris  ;  in  this  situation  it  grows  and  copulation  takes  place,  after  which 
the  males  die  off,  this  explaining  why  they  are  so  rarely  met  with  in  the  excrement. 
It  is  only  after    the    eggs   have  developed"    that    the   females  wander  into  the  large 
intestine  and  reach  the  outer  world.     According  to  another  statement,  the  vermiform 
appendix  is  said  to  be  the  normal  abode  of  Oxyuris  in  children. 

2  Simons  removed  a  specimen  from  the  cervical  canal  of  the  uterus  (Ctrlbl.  /.  GynakoL 
1899,  p.  26  ;    C.  f.  B.,  P.  u.  I.  [i],  xxvi.,  p.  235). 


340  THE   ANIMAL    PARASITES    OF    MAN 

play  a  part  in  the  distribution  of  the  parasite  similar  to  that  demonstrated 
by  Grassi  as  taking  place  in  the  spread  of  the  ova  of  Trichocephalus  and 
Tamia. 

The  assumption  of  a  direct  development  without  an  intermediary 
host  was  first  substantiated  by  Leuckart  by  experiments  on 
himself  and  three  of  his  students  ;  about  fourteen  days  after 
swallowing  the  eggs  the  oxyuris  has  attained  6 — 7  mm.  in  length  ; 
Grassi,  and  later  on  Calandruccio,  infected  themselves  by  swallowing 
adult  female  oxyuris,  with  the  same  results. 

LITERATURE. 

Vix,    E.     Ueber   Entozoen    bei   Geisteskranken,   insbes.    iiber     .     .     .     Oxyuris   ver- 

micularis.     (Allg.  Zeitschr.  f.  Psych.,  1860,  xvii.,  p.  149.) 
STRICKER,    W.     Physpath.    Bemerk.    iib.    Ox.    verm.     (Virchow's    Arch.,    1861,    xxi., 

p.  360.) 
FLOGEL,  J.  H.  L.     Ueb.  d.  Lippen  einiger  Oxyuris- Arten.     (Z.  f.  w.   Z.,   1869,  xix., 

p.  234.) 
MICHELSON.     Die  Oberhaut  der  Genitocruralfalte  u.   ihre   Umgebung  als  Brutstatte 

von  Ox.  verm.     (Berl.  klin.  Wchnschrft.,   1877,  xiv.,  No.   33.) 
GRASSI,  B.     I  malefizi  delle  mosche.     (Gaz.  degli  ospitali,  1883,  No.  59.) 
WINDELSCHMIDT,     Ein  Fall  von  langjahr.     Reflex-Epilepsie  in  Folge  von  Ox.  verm. 

(Allg.  med.  Centralztg.,  1883,  p.  606.) 
PROSKAUER,   TH.     Embryonen  von   Oxyuris  in   der  Nase.     (Zeitsch.    f.   Ohrenhlkde, 

1891,  xxi.,  p.  310.) 

GORDIACEA. 

Very  long  thin  worms  similar  to  filariae,  which,  in  their  adult  condition, 
live  free  in  brooks,  pools  and  springs  ;  the  mouth  and  the  commencement 
of  the  intestine  are  obliterated  ;  there  are  no  lateral  ridges,  and  the  muscular 
system  presents  a  structure  different  to  that  of  the  nematoda.  The  posterior 
end  of  the  male  is  split,  and  spicules  are  lacking  ;  there  are  two  testicles. 
In  both  sexes  the  genitalia  discharge  through  the  terminal  gut. 

The  larvae,  which  carry  a  rostrum  beset  with  hooks,  force  themselves 
into  the  larvae  of  water-insects  ;  more  rarely  they  invade  molluscs,  and 
they  then  become  encysted  within  the  body  of  the  host.  According  to  Villot, 
at  least  a  part  of  them  attain  the  intestine  of  fishes,  where  they  again  become 
encysted,  and  after  a  period  of  rest  they  travel  into  the  tissues  of  their  hosts, 
and  finally  again  reach  the  exterior  by  way  of  the  intestine,  where  they  then 
become  adult.  In  most  cases,  however,  the  gordius  larvae  are  taken  up 
by  predacious  water  insects  ;  they  live  for  a  while  in  the  body-cavity  of 
these  insects  undergo  a  metamorphosis,  and  finally  wander  into  the  water. 

A  few  species  invade  man  accidentally  with  water,  in  which  case  they 
are  usually  vomited  up  : 

Gordius  aquaticus,  Dujardin,  30 — 90  cm.  in  length  (Aldrovandi,  Degland, 
Siebold,  Patruban). 

Gordius  tolosanus,   Duj.,    u — 13   cm.  in  length  (Fiori). 

Gordius  varius,  Leidy,   10 — 16,  Weibch.,  up'  to  30  cm.  in  length  (Diesing), 

Gordius  chilensis,  Blanch.  (Guy).  Gordius  villoti,  Rosa  (Bercutti,  Came- 
rano)  ;  Gordius  tricuspidatus ,  L.  Def.  (R.  Blanchard),  Gordius  violaceus, 
Baird  (Topsent)  and  G.  pustulosus,  Baird  (Parona). 


ACANTHOCEPHALA  341 

LITERATURE. 

ALDROVANDI,  U.     De  animalibus  insectis,  1638,  Book  VII.,  Chap,  x.,  p.  720. 
DEGLAND,  C.  D.     Descr.  d'un  ver  filiforme  rendu  par  vomiss.     (Rec.  trav.  soc.  d'amat 

d.  sc.,  de1  1'agricult.  et  des  arts  de  Lille,  1819-22,  p.  166.) 
SIEBOLD,   C.   TH.    v.     Ueber   d.    Fadenwiirm.   d.    Insect.     (Stett.   entom.    Ztg.,    1854, 

xv.,  p.  107.) 
DIESING,  C.  M.     Rev.  d.  Nemat.     (Stzgsb.  k.  k.  Ac.  d.  Wiss.  Wien.  math.-nat.  Cl.. 

1880,  xlii.,  p.  604.) 

PATRUBAN,  v.     Vork  v.  Gord.  aq.  b.  Mensch.     (Wien.  Med.  Jhrb.,  1875,  p.  69.) 
CAMERANO,   L.     Ric.  int.  al  parassit.  ed  al  polimorf.  dei  Gord.     (Mem    R.  Ace.  sc., 

Torino,  1887  [2],  xxxviii.,  p.  395.) 
Monografia  d.  Gordii.     (Ibid.,   1897,  xlvii.) 
BLANCHARD,    R.     Pseudoparas.    d'un   Gord.    chez   l'homme.     (Bull.    Ac.    de   med.    de 

Paris,   1897,  xxxvii.,  p.  614.) 
TOPSENT,   E.     Sur  un  cas  de  pseudopar.   chez  I'homme  du   Gord.   viol.     (Bull.   soc. 

scient.  et  med.  de  1'Ouest.,  1900,  ix.,  No.  i.) 
PARONA,   C.      Altro  caso  di  pseudopar.   d.   Gordio  nell'   uomo.     (Clinica  Med.   Ann., 

1901,  No.  10.) 


D.     ACANTHOCEPHALA     (Rud.) 

Gutless,  nematode-like  worms  that  carry  at  their  anterior  end  a  retractile 
rostrum  beset  with  hooks.  In  their  adult  condition  they  only  live  in  verte- 
brate animals.  During  their  larval  stage  they  are  often  parasitic  in  inverte- 
brate animals. 

The  Acanthocephala  are  elongated  cylindrical  worms,  with  a  rounded 
posterior  end.  In  some  species  an  annulation  is  distinctly  recognisable  ; 
they  are,  however,  not  segmented.  The  size  varies  according  to  the  species, 
between  about  5 — 10  mm.  and  40 — 50  cm.  ;  in  general,  however,  there  is  a 
preponderance  of  the  small  species.  The  sexes  are  separate,  and  the  males 
can  easily  be  distinguished  from  the  females  without  examination  of  the 
genitalia,  as  the  females  are  both  larger  and  thicker. 

The  body  wall  of  Echinorhynchus  is  limited  by  a  thin  cuticle, 
which  is  attached  inwardly  to  the  hypodermis.  In  only  exceptional  cases 
a  syncytium  with  large  nuclei,  even  in  the  adult  condition,  is  represented 
by  the  hypodermis  ;  and  in  it  fibre  systems,  the  elements  of  which  run 
in  layers  in  various  directions,  appear,  and  it  is  only  towards  the  interior 
from  these  strata  of  fibres  that  the  nuclei  of  the  hypodermis  are  found. 
As  a  rule,  these  fibres,  at  all  events  the  radiary  fibres,  are  regarded  as 
muscles.  Hamann  describes  them  as  elastic  fibres,  which  lie  in  a  viscid 
gelatinous  connective  substance  (transformed  protoplasm  ?) ;  a  lacune  system 
filled  with  a  granular  fluid,  the  central  part  of  which  are  two  longitudinal 
lacunes  lying  at  the  sides,  also  belongs  to  the  cutaneous  strata,  as  do  the 
so-called  lemnisci,  two  short,  flat  organs  suspended  in  the  body  cavity,  and 
the  pedicles  of  which  are  attached  anteriorly  at  the  border  between  the 
rostrum  and  body;  their  structure  as  well  as  their  origin  permit  them 
to  be  traced  to  the  skin  (fig.  223). 

Finally,  inwardly  below  the  skin  there  follows  a  layer  of  annular,  and  after 
these  a  layer  of  longitudinal  muscles,  the  structure  cells  of  which  remain 
present  in  the  residues,  carrying  nuclei.  The  motor  apparatus  of  the  rostrum, 
the  sheath  of  the  rostrum,  and  the  lemnisci  also  belong  to  the  muscular 


342  THE    ANIMAL   PARASITES    OF    MAN 

system.  The  rostrum  represents  a  finger-shaped  hollow  process  of  the 
cutaneous  layer  ;  but,  according  to  Hamann,  it  originates  from  the  entoderm 
and  passes  through  the  skin  secondarily.  It  is  covered  by  a  thin  cuticle 
and,  as  a  rule,  contains  a  large  number  of  regularly-placed  chitinous  hooks 
that  adjoin  a  granular  formation  tissue.  From  the  base  of  the  rostrum 
springs  a  tubular  hollow  muscle  extending  into  the  body  cavity — this  is  the 
Receptaculum  proboscidis — from  the  base  of  which  again  bundles  of  longitudinal 
muscles  originate,  which  pass  along  its  axis  and  that  of  the  rostrum  itself, 
and  are  inserted  at  the  inner  surface  of  its  anterior  end  (retractor  proboscidis). 
These  muscles  when  they  contract  invaginate  the  proboscis  and  draw  it  into 
the  receptaculum  ;  when  reversed  they  act  again  as  protrusor  proboscidis  - 
The  whole  of  the  anterior  body,  however,  can  be  invaginated,  and  for  this 
purpose  there  is  a  muscle  that  originates  from  the  body  wall  at  a  variable 
distance  back,  and  which  is  joined  to  the  receptaculum  (retractor  receptaculi)  ; 
there  is  also  a  bell-shaped  muscle  which  springs  from  the  body  wall 
behind  the  lemnisci  in  rings,  and  passes  forward  to  the  spot  of  attach- 
ment of  the  lemnisci. 

The  nervous  system  consists  of  a  cluster  of  ganglia  situated  at  the 
base  of  "the  rostrum,  from  which  three  nerves  pass  towards  the  front  and  two 
towards  the  back.  No  sensory  organs  are  known. 

The  excretory  organs,  according  to  Kaiser,  lie  at  the  upper  border 
of  the  ductus  ejaculatorius  in  the  male,  and  at  the  so-called  bell  in  the 
female.  Here  they  represent  the  long-known  villous  tufts,  placed  on  disc- 
like  cushions.  In  each  of  the  cylindrical  villi — which  terminate  blindly 
towards  the  body  cavity — there  lies  a  cilium,  which  springs  from  the  mem- 
brane lining  the  villus,  and  which  lies  in  a  space  cavity  of  the  villus, 
which  ultimately  proceeds  as  a  little  canal.  There  are  three  canals  discharging 
into  the  uterus  that  serve  to  conduct  the  excretory  materials  from  the  body 
cavity ;  special  glandular  cells  corresponding  to  the  terminal  cells  of  the 
platyhelminths,  at  the  commencement  of  the  system,  are  not  present  in 
the  acanthocephala. 

Sexual   Organs. 

A. — Male  organs.  The  greatest  part  of  the  male  genital  apparatus  is 
contained  in  a  muscular  sheath — the  ligament — which  originates  at  the 
posterior  end  of  the  receptaculum  proboscidis,  passes  along  longitudi- 
nally through  the  body  cavity,  and  is  inserted  at  the  posterior  end  of 
the  worm.  The  two  oval  testicles  usually  lie  one  behind  the  other ;  their 
vasa  efferentia  unite  sooner  or  later  into  a  vas  deferens  which  passes 
backwards,  and  finally  terminates  in  the  penis  j  the  terminal  portion  of  the 
conducting  apparatus  is  surrounded  by  six  large  glandular  cells  (prostatic 
glands),  the  excretory  ducts  of  which  open  into  the  vas  deferens.  The 
penis  itself  is  placed  at  the  base  of  a  bell-shaped  invagination  of  the 
posterior  end,  the  bursa,  which  is  everted  during  copulation. 

B. — Female  organs.  There  are  only  two  ovaries  present  in  the  liga- 
ment during  the  larval  stage.  During  the  course  of  growth  they  divide 
into  accumulations  of  cells  (placentulae,  loose  or  floating  ovaries),  which 
finally  cause  the  ligament  to  burst,  and  they  thus  attain  the  body  cavity. 


ACANTHOCEPHALA 


343 


Thence  a  peculiarly  constructed  apparatus  finally  conveys  the  eggs  out. 
This  apparatus  consists  of  the  uterine  bell  and  vagina  ;  the  latter  dis- 
charging at  the  posterior  extremity  of  the  body.  The  belJ  is  a  muscular 

canal  provided  with  apertures  at  both  the  anterior 
and  posterior  extremities.  Its  interior  space  is 
in  direct  communication  with  the  body  cavity, 
and  the  anterior  orifice  takes  up  all  material 
floating  in  the  cavity — egg-balls,  mature  and  im- 
mature eggs — and  pushes  these  further  back- 
wards. The  continuation  of  the  bell-lumen  is 
now  narrowed  by  a  number  of  large  cells  in 
such  a  manner  that  only  bodies  of  a  certain 
form  can  pass  through  this  tract  and  attain  the 
uterus  ;  everything  else  is  conveyed  back  into 
the  body  cavity  through  the  posterior  opening 
of  the  bell. 

The  eggs  are  already  fertilised  in  the  body 
cavity,  and  in  this  locality  go  through  their  de- 
velopment to  the  formation  of  the  embryo. 
Completely  developed  eggs  are  surrounded  by 
three  shells,  and  are  generally  fusiform.  The 
eggs  agglomerate  in  masses  in  the  uterus  until 
they  are  finally  deposited  through  the  vagina 
and  vulva.  For  the  further  development,  the 


R.r. 


FIG.  223.  —  The  male  of 
Echinorhynchus  angustatus. 
25/1.  L.,  lemnisci  ;  T.,  tes- 


FIG.  224. — Anterior  portion  of  the  female  apparatus 
of  Echinorhynchus  acus  (magnified).     (After  Wagener.) 


tides ;    P.,  prostatic  glands  ;  On    the    left    seen    from   behind,    on   the   right   seen 

Pr.,  sheath  of  proboscis,  with  from  the  front.     F.,  Inferior  orifice   of  the   bell;   B., 

ganglion;    R.r.,    retractor  of  bell ;  Lig.,  ligament;   M.,  mouth  of  bell ;  Ut.,  uterus, 
sheath  of  proboscis. 

transmission  of  the  eggs  into  an  intermediary  host,  usually  a  crustacean 
or  an  insect,  is  necessary  ;  the  metamorphosis  is  very  complicated  ;  but 
this  transmission  may  be  very  easily  effected  artificially  by  feeding  suitable 
crustaceans  (asellus,  gammarus,  &c.)  with  the  eggs  of  acanthocephala  ;  this 
being  the  only  method  of  inducing  the  larva  to  hatch  out  so  that  its 


344  THE    ANIMAL   PARASITES   OF   MAN 

structure  may  be  studied.  The  larva  appears  in  the  form  of  an  elongated, 
somewhat  bent  body  at  the  stumpy  anterior  end  of  which  there  is  a  crown 
of  hooks  or  spines  ;  whereas  the  posterior  end  is  pointed.  Especial  retractors 
draw  in  the  hook-beset  anterior  surface,  and  an  elastic  cushion. beneath  them 
roundish  heap  of  small  cells  are  seen,  from  which  the  entire  body  of 
jerks  them  forward  again  when  required.  In  the  middle  of  the  body  a 
the  echinorhynchus  originates,  even  to  the  cutaneous  layer  ;  the  latter  is  also 
the  larval  skin  in  which  the  small  echinorhynchus  gradually  grows.  The 
development  of  all  the  organs  takes  place  within  the  intermediary  host,  and  the 
parasite  only  needs  to  be  imported  into  the  terminal  host  to  attain  the  adult 
stage  after  a  certain  growth.  In  some  cases,  however,  a  second  intermediary 
host  is  utilised. 

Species  of  acanthocephala  only  occur  exceptionally  in  human  beings. 


I.     Echinorhynchus  gigas,  Goeze,  1782. 
Syn.  :   Tcenia  hirudinacea,  Pallas,   1781. 

The  body  is  elongated,  gradually  decreasing  in  thickness  towards  the 
back,  The  rostrum  is  almost  spherical,  and  is  beset  with  five  or  six 
rows  of  recurved  hooks.  The  males  measure  10 — 15  cm.  in  length,  the 
females  30 — 50  cm.  ;  the  eggs  are  provided  with  three  shells,  of  which 
the  middle  one  is  the  thickest.  The  eggs  measure  0*08 — 01  mm.  in 
length.  The  GIANT  ECHINORHYNCHUS  occurs  especially 
in  the  intestinal  canal  of  the  domestic  pig  ;  it  is  less 
common  in  other  mammals.  It  bores  deep  into  the 
mucous  membrane  with  its  rostrum,  and  causes  an 
annular  proliferation  around  the  perforated  spot  ;  occa- 
sionally also  it  causes  perforation  of  the  intestine. 

It  is  doubtful  whether  the  giant  echinorhynchus  occurs 
in  man.  Leuckart  admitted  that  there  were  a  few  positive 
cases.  According  to  Lindemann,  Ech.  gigas  occurs  in 
human  beings  in  South  Russia,  and  its  presence  is  not 
of  lEcJrinorhync1nfs  rare-  This  statement,  however,  has  not  been  confirmed, 
gigas.  300/1.  (After  Its  presence  in  man  is  by  no  means  impossible,  as  its 
Leuckart.)  intermediary  host,  the  cankerworm,  or  cockchafer 

(Melolontha),     is,     according     to     Schneider,    occasionally 

eaten  raw  by  human  beings.  According  to  Kaiser,  the  golden  beetle 
(Cetonia  aurata),  and,  according  to  Stiles,  another  beetle  in  America  (Lach- 
nosterna  arcuata}  are  also  intermediary  hosts. 


2.     Echinorhynchus  hominis,  Lambl,  1859. 

This  term  is  applied  to  an  ECHINORHYNCHUS  found  by  Lambl  in  the 
intestine  of  a  boy  who  had  died  of  leuccemia  ;  the  worm  was  5 '6  mm.  in 
length,  and  the  almost  spherical  head  was  beset  with  twelve  transverse  rows 
of  hooks. 


HIRUDINEA   S.    DISCOPHORA  345 

3.     Echinorhynchus  moniliformis,  Bremser,  1819. 

The  male  is  4  cm.  in  length,  the  female  8  cm.  long.  This  species 
lives  in  the  intestine  of  field-mice,  rats,  marmots  and  Myoxus  qucrcinus. 
A  beetle,  Blaps  mucronata,  is  the  intermediary  host. 

This  species  has  also  once  been  artificially  cultivated  in  man  (Grassi  and 
Calandruccio). 

LITERATURE. 

LAMBL,    W.     Micr.    Unters.    d.    Darm-Excrete.       (Prag.    Vierteljahrsschft.     f.    pract. 

Hlkde.,  1859,  Ixi.,  p.  45.) 
SCHNEIDER,  A.     Entw.  d.  Ech.  gigas.     (Stzgsb.  d.  oberh.   Ges.  f.  Natur-  u.  Hlkde., 

1871,  p.  i.) 

LEUCKART,  R.  Commentatio  de  statu  embryonal!  et  larv.  Echinorh.  .   .  .  Lipsiae,  1873. 
KAISER,  J.     Ueber  die  Entw.  d.  Ech.  gigas.     (Zool.  Anz.,  1887,  x.,  p.  414.) 
GRASSI,  B.,  and  CALANDRUCCIO.     Ueb.  einen  Ech.,  der  auch  im  Menschen  parasitirt. 

.     .     .     .     (C.  f.  B.  u.  P.,   1888,  iii.,  p.  521.) 

HAMANN,  O.     Die  Nemathelminthen.     I.  Monogr.  d.  Acanthoceph.     Jena,  1891. 
STILES,   C.   W.     Sur    1'hote  intermediaire  de  1'Ech.   gig.   en  Amerique.      (C.   R.   soc. 

biol.,  Paris,  1891  [9],  iii.,  p.  764.) 

KAISER,   J.   E.     *Die  Acanthocepha  lenund  ihre  Entwickelung.     Cassel,    1893.     (Bibl. 
zoologica,  vii.) 


E.     HIRUDINEA  s.    DISCOPHORA,  Leech. 

The  Hirudinea,  which  have  been  appropriately  included  amongst  the 
annelida,  differ  in  many  respects  from  the  typical  members  of  the  group  ; 
their  body  is  long  and  flat,  it  lacks  the  pai^rjpdia  that  are  characteristic 
to  all  forms  of  aqjoelida  ;  but,  on  the  other  hand,  possesses  a  terminal 
posterior  sucker,  and  in  many  species  there  is  also  an  anterior  sucker. 
The  mouth  is  terminal  at  the  anterior  end,  the  anus  lies  dorsally  above  the 
posterior  sucker  (fig.  226).  The  body  is  segmented,  but  this  is  less  mani- 
fest in  the  body  covering  than  it  is  in  the  arrangement  of  the  internal 
organs  ;  the  segmentation,  nevertheless,  is  also  indicated  exteriorly  by  the 
appearance  of  the  cutaneous  sensory  organs  which  correspond  to  the  seg- 
ments. This  shows  what  the  condition  of  the  ganglia  in  the  abdominal 
ganglion  chain  has  taught  us,  that  the  anterior  and  the  most  posterior 
segments  are  considerably  abbreviated — a  part  of  the  latter  taking  part  in 
the  formation  of  the  suctorial  organs.  In  a  great  many  species  the  skin  is 
distinctly  annulated,  four  or  five  of  such  rings,  at  least  in  the  central  region  of 
the  body,  appearing  on  one  segment  of  the  body.  The  condition  of  their 
body  cavity  is  another  peculiarity  of  the  Hirudinea ;  it  is  narrowed  by 
the  powerful  development  of  the  connective  tissue  and  the  muscular 
system  into  four  tubular  sinuses,  which  have  the  appearance  of  blood-vessels. 
There  are  usually  one  dorsal  and  one  ventral  median  trunks,  as  well  as  two 
lateral  trunks  ;  in  addition,  a  particular  blood-vessel  system  exists. 

The  skin  consists  of  a  very  thin  cuticle  that  is  cast  off  from  time  to 
time,  it  is  secreted  by  the  underlying  cylindrical  epithelium,  which  contains 
numerous  goblet  cells.  The  muscular'  system  is  strongly  developed  ;  it  consists 
of  long  tubular  fibres,  which  run  circularly,  longitudinally  and  in  the 


346 


THE  ANIMAL  PARASITES  OF  MAN 


m 


dorso-ventral  direction  ;  the  muscular  system  is  subject  to  a  particular 
expansion  in  the  clinging  organs  and  at  the  commencement  of  the  intestine. 
On  the  whole,  the  alimentary  canal  represents  a  tube  running  straight  from 
the  mouth  to  the  anus,  which  possesses  a  number  of 
blind  sac-like  protuberances  at  the  sides  varying  according 
to  the  species.  The  most  anterior  section,  the  pharynx, 
in  the  leeches  with  maxillae,  carries  three  chitinous,  semi- 
circular plates  furnished  with  teeth — the  jaws  —  which 
serve  to  tear  up  the  epidermis  in  order  to  open  the 
blood-vessels  ;  in  the  .  leeches  with  rostra  a  long  pro- 
tractile proboscis  rises  from  the  base  of  the  elongated 
pharynx.  Numerous  salivary  glands,  the  secretion  from 
which  possesses  toxic  properties,  discharge  into  the 
pharynx.  The  oesophagus,  which  follows  the  pharynx, 
and  to  the  exterior  of  which  numerous  radiary  muscles 
are  fixed,  is  a  suctorial  organ  in  its  entire  structure. 
The  nutriment  in  the  larger  species  consists  of  the 
blood  of  vertebrate  animals,  in  smaller  species  and 
in  the  young  stages  the  food  consists  of  small  inver- 
tebrate animals. 

The  NERVOUS  SYSTEM  exhibits  the  typical  structure 
of  other  segmented  worms  ;  the  sensory  organs  consist 
of  the  above-mentioned  goblet-shaped  cutaneous  sensory 
organs,  of  the  organs  of  taste,  and  of  eyes  ;  the  latter 
frequently  being  present  in  large  numbers. 

The  EXCRETORY  or  segmental  organs  exhibit  many 
peculiarities,  which  cannot,  however,  be  detailed  here. 
They  commence  with  funnels  in  the  lacunes  of  the  body 
cavity,  and  usually  discharge  on  the  ventral  surface. 

Almost  all  the  hirudinea  are  hermaphrodite  and 
copulate  reciprocally.  The  two  ovaries  are  very  small, 
and  the  oviducts  that  proceed  from  them  soon  unite 
into  a  common  duct,  which  then  goes  over  into  the 
uterus  and  discharges  through  the  short  vagina  in  the 
median  line  of  the  ventral  surface  behind  the  male 
organs  into  the  so-called  clitellar  region.  The  male 
sexual  apparatus  consists  of  symmetrically  -  arranged 
testicles,  varying  in  number  according  to  the  species, 
the  short  vasa  efferentia  of  which,  one  by  one,  run  into 
the  vas  deferens,  passing  towards  the  front  on  each  side. 
In  front,  at  about  the  level,  or  a  little  in  front  of,  the 
female  genitalia,  the  two  vessels  pass  into  a  convoluted 
mass  of  tubes  to  the  so-called  epididymis,  and  then 
discharge  into  the  single  protractile  penis  (fig.  226). 

All  leeches  deposit  so-called  COCOONS.  These  are 
small  barrel-shaped,  or  pouch-like  bodies,  which  are 
surrounded  by  a  thicker  shell,  and  contain  a  number 

of  eggs  in  a  large  mass  of  albumen  ;  the  albumen  originates  from  glands 
of  the  generative  organs,  the  shell-substance  from  cutaneous  glands  of  the 
clitellar  region. 


FIG.  226.  —  The 
internal  organs  of 
the  leech.  The 
creature  has  been 
opened  from  the 
dorsal  surface,  and 
part  of  the  intestine 
has  been  removed. 
The  testicles,  with 
vas  deferens,  may 
be  seen  between 
the  blind  ducts  of 
the  intestine  ;  be- 
yond these  on  either 
side  the  segmental 
organs.  The  female 
genital  organs  are 
in  front  of  the  most 
anterior  pair  of  tes- 
ticles. (After  Ken- 
nel.) 


HIRUDO   MEDICINALIS 


347 


I.     GnathobdellidcB t  leeches  with  jaws. 

These  are  distinguished  by  the  possession  of  usually  three  jaws  in  the 
pharynx ;  the  body  consists  of  twenty-six  segments.  The  posterior  sucker 
is  large  and  flat  ;  the  anterior  sucker  is  smaller.  The  Hirudinea  have 
five  pairs  of  eyes,  the  Nephelincs  have  four  pairs. 


Gen.  Hirudo,  L.,  1758. 

The  entire  body  consists  of  102  annulations  ;  five  appearing  on  one 
segment  in  the  central  region  of  the  body.  The  pharynx  has  three 
semi-circular  jaws,  the  arched  border  of  which  is  beset  with  numerous 
teeth  (50 — 100).  The  male  sexual  orifice  lies  between  the  thirtieth  and 
thirty-first  rings,  the  female  orifice  between  the  thirty-fifth  and  thirty- 
sixth.  There  are  numerous  species,  some  of  which  are  utilised  for  medi- 
cinal purposes. 

i.     Hirudo  medicinalis,  L.,  1758. 

It  occurs  in  numerous  colour  varieties,  one  of  which  has  been 
designated  Hirudo  officinalis,  Moq.  Tandon.  Usually  the  dorsal  surface  is 
greyish-green,  and  is  marked  with  six  rusty- 
red  longitudinal  stripes.  The  ventral  surface 
is  olive-green,  more  or  less  spotted  with  black, 
and  marked  at  the  sides  with  a  black  longi- 
tudinal line.  The  length  averages  8  to  12 — 
20  cm.  This  leech  lives  in  swamps,  ponds  and 
brooks,  overgrown  with  plants  and  having  a 
muddy  bed.  The  cocoons  are  deposited  in  the 
soil  at  the  sides.  Europe,  as  well  as  N.  Africa, 
is  its  home.  At  the  present  day  it  has  been 
exterminated  from  most  parts  of  Central  Europe, 
but  it  is  still  very  common  in  Hungary.  Its 
use  for  medicinal  purposes  is  well  known.  A 
large  leech  can  suck  about  15  grs.  of  blood 


a  I 

FIG.  227. — Hirudo  medicin- 
alis. (a)  Anterior  end,,  with 
open  buccal  cavity,  with  the 
jaws  (/.)  at  the  base  ;  (b)  one 


and    about    the    same    amount    is    lost    through     jaw  isolated.     (After  Claus.) 
secondary  haemorrhage. 


2.     Himdo  troctina,  Johnston,  1816. 
Syn.  :  Hirudo  inter  rupta,  Moq. -Tandon,  1826. 

This  species  measures  8— 10  cm.  in  length.  The  back  is  greenish,  with 
six  rows  of  black  spots  surrounded  by  red  ;  the  lateral  borders  are  orange- 
coloured  ;  the  abdomen  spotted  or  unspotted.  Its  habitat  is  in  N.  Africa 
and  Sardinia.  It  is  applied  medicinally  in  England,  Spain,  France, 
Algeria,  &c. 


34$  THE    ANIMAL    PARASITES    OF    MAN 

Gen.  Limnalis,  Mq.-Tandon,   1826. 

Nearly  related  to  hirudo,  but  is  differentiated  by  a  longitudinal  groove 
on  the  inner  surface  of  the  upper  lip  of  the  anterior  sucker.  The  jaws 
are  furnished  with  over  100  very  sharp  toothlets. 


3.     Limnatis  nilotica,  Savigny,   1820. 

Syn.  :  Bdella  nilolica,  Sav.  ;  L.  nilotica,  Moq.-Tandon ;  Htemopis  (vcrax) 
Moq.-Tandon,  1826,  p.  p.  ;  Hcemopis  sanguisuga,  Moq.-Tandon,  1846  (nee 
Hir.  sanguis  Bergm.,  1757). 

This  species  measures  8 — 10  crn.  in  length,  and  becomes  gradually  more 
pointed  towards  the  front  ;  the  body  is  always  soft.  The  back  is  brown 
or  greenish,  and  has  usually  six  longitudinal  rows  (rarely  only  two  or 
four)  of  black  dots.  The  abdomen  is  dark ;  but  numerous  colour  varia- 
tions occur. 

The  native  place  is  N.  Africa,  especially  the  coastal  regions  ;  it  is  also 
found  in  the  Canaries,  the  Azores,  Syria,  Armenia,  Turkestan,  perhaps  also 
Southern  Europe.  It  is  taken  into  the  mouth  with  drinking  water,  and 
may  settle  in  the  pharynx,  larynx,  oesophagus,  and  nasal  cavities  of  human 
beings.  This  species  has  also  been  observed  in  the  vagina  and  on  the 
conjunctiva.  It  is  equally  fond  of  attacking  domestic  animals. 

Hirudo  mysomelas  (Senegambia)  and  H.  granulosa  (India)  are  placed 
with  this  genus,  and,  like'  our  leech,  are  also  used  for  medicinal  purposes. 

Gen.  Hcemadipsa,  Tennent,  1861. 

These  leeches  live  on  land,  and'tneasure  2 — 3  cm.  in  length.  About 
a  dozen  species  are  known.  They  are  a  veritable  scourge  to  persons  in 
the  Tropics  (Asia,  South  America),  as  they  attack  them  to  suck  their 
blood.  They  are  able  to  force  their  way  even  under  close-fitting  garments, 
so  that  it  is  difficult  to  protect  oneself  from  their  assaults  (H.  ceylonica, 
Bl.,  and  other  species). 


2.     Rhynchobdellidce,  leeches  with  rostrum. 

These  are  furnished  with  a  proboscis  in  lieu  of  the  jaws  ;  the  segment 
consists  of  three  annulations. 

Gen.  Hcementaria,  de  Filippi,  1849. 

H.  officinalis,  de  Fil.  Inhabit  Mexico,  where  they  are  used  for  medicinal 
purposes. 

Gen.  Placobdella,  R.  Blanch. 

PI.  catenigera,  Moq.-Tandon.  Indigenous  of  South  Russia,  Hungary, 
Italy  and  South  France.  It  is  a  parasite  of  the  swamp  turtle,  but  frequently 
attacks  human  beings. 


ARTHROPODA 


LITERATURE. 


349 


MoyuiN-TANDON.     Monogr.  cle  la  fam.  des  Hirudinees,  2nd  edit.,  Paris,  1846. 

EBRARD.     Nouv.  monog.  des  sangs.  medic.     Paris,  1857. 

WHITMAN,  C.  O.     The  external  morph.   of  the  Leech.     (Proc.   Amer.   Acad.  of  Arts 

and  Sc.,   1884,  xx.,  p.  76.) 

The  Segm.  Sense  Organs  of  the  Leech.    (Amer.  Naturalist,  1884,  xviii.,  p.  1 104.) 
The  Leeches  of  Japan.     (Quart.  Journ.  of  Micr.  Sc.,  1886  [2],  xxvi.,    p.  317.) 
APATHY.     Analyse  d.   auss.   Korperf.   d.   Hirudineen.     (Mitth.  d.   zool.  Stat.  Neapel 
1888,  viii.,  p.    153.) 

Siisswasser-Hirudineen.     (Zool.  Jahrb.  Abth.  f.  Syst 1888^.725.) 

BLANCHARD,  R.  Art.  Hirudinees.  (Dist.  encycl.  d.  sc.  Med.,  1888,  xiv.,  p.  129,  and 
C.  R.  soc.  biol.,  Paris,  17  Oct.,  1891  ;  as  well  as  in  Bull.  soc.  zool.,  France, 
1890-99.) 

LEUCKART,  R.  D.  Paras  d.  Menschen.  (2nd  edit.,  i  vol.,  ii.,  Hirudineen  continued 
by  G.  Brandes.  Lpz.,  1886-1901.) 


F.     ARTHROPODA.     (Jointed-limbed  Animals  ) 


Bilaterally  symmetrical  segmented  animals  which  'are  covered  with  a 
thick  cuticle  that  is  frequently  calcareous  (crustacea,),  but  always  thinner 
between  the  segments  ;  they  carry  (primitively)  a  pair  of  jointed  appendages 
on  every  segment.1  The  segments  of  the  body  are  uniform  in  certain 
regions,  but  differ  from  those  of  contiguous  regions,  so  that  it  is  easy  to 
distinguish  three  parts  (head,  thorax,  and  abdomen),  each  composed  of 
segments.  The  cephalic  segments  are  always  formed  into  an  uniform  head, 
the  segmentation  being  scarcely  recognisable  at  either  end  ;  the  thoracic  seg- 
ments may  also  fuse,  or  part  or  all  of  them  may  coalesce  with  the  head  ; 
the  abdomen,  as  a  rule,  retains  its  segmentation  ;  but  this  may  possibly  also 
be  lost,  in  which  case  it  is  [sometimes,  F.  V.  T.]  united  to  the  cephalo- 
thorax.  The  structure  of  the  three  regions  depends  mostly  on  the  varying 
form  and  function  of  the  appendages — those  on  the  head  are  primitively 
locomotive  organs  (and  frequently  are  still  so  in  the  early  stages),  but 
they  become  transformed  into  feelers  and  mouth-parts  (mandibles,  maxillae) ; 
the  limbs  of  the  thorax,  however,  usually  retain  their  ambulatory  func- 
tions, as  frequently  do  those  of  the  abdomen  ;  sometimes,  however,  the  abdo- 
minal limbs  disappear,  entirely  or  partly  ;  in  the  latter  case  they  are  then 
utilised  for  other  purposes. 

In   their  organisation   the  Arthropoda  approach   to   the  segmented  worms. 

The   Arthropoda   are   generally   divided   into   five   groups   (Crustacea?    Pro- 


1  [In  most  Arthropoda  the  skin  is  hardened  by  a  deposit  of  chitin  (Hexapoda,  &c.). 
— F.  V.  T.] 

-  Parasitic  or  free-living  crustaceans  may  now  and  then  invade  man  abnormally. 
Thus,  according  to  Betten,  Caligus  curtus  invade  the  cornea  (Betten,  R.  A.,  "  Par.  Crust 
as  a  Foreign  Body  on  the  Cornea,"  Lancet,  1900,  i.,  p.  1002  ;  and  Centralbl.  fur  Bakt.t 
Paras,  u.  Infekt.,  xxix.,  p.  506).  According  to  Laboulbene,  Gammarits  pulex  (Laboul- 
bene,  A.,  "  Obs.  d'accid.  caus.  par  le  G.  pul.  apport.  avece  I'eau  de  boison  dans  Vestomac 
d'un'homme,"  Bull.  Ac.  mfd.,  1898,  p.  21). 


35°  THE  ANIMAL  PARASITES   OF    MAN 

tracheata,    Arachnoidea,    Myriapoda,1    and    Insecta    or    Hexapoda},    of    which 
only  the  Arachnoidea  and  the  Hexapoda  interest  us  here. 

A. — Arachnoidea    (Spiders,    Mites,    &c.). 

The  head  and  thorax  are  always  united  together  ;  the  abdomen 
is  either  segmented  or  without  exterior  segmentation,  in  which  case 
it  is  united  with  the  cephalothorax.2  The  number  of  pairs  of  appen- 
dages amount  to  six,  of  which  the  two  front  pairs,  the  chelicerae 
and  the  pedipalpi,  are  attached  to  the  head  region  and  the  four 
remaining  pairs  to  the  thoracic  region.3  The  abdomen  in  the 
adult  condition  has  no  appendages.  The  arachnoids  are  air- 
breathers,  and  for  this  purpose  are  either  provided  with  trachea?, 
or  with  so-called  lung  sacs,  or  they  breathe  through  the  surface 
of  the  body. 

There  are  eight  or  ten  orders  of  arachnoids,  of  which,  however, 
only  two,  the  Acarina  and  the  Linguatulida,  have  to  be  considered 
here.4 

Order  Acarina  (Mites). 

Small  arachnoids,  the  three  parts  of  the  body  of  which  are,  as  a  rule, 
coalesced  ;  it  is  only  rarely  that  a  faint  line  indicates  the  division.  The 
two  appendages  on  the  head  are  designed  for  biting  or  puncturing  and 
sucking,  and  vary  according  to  their  use.  The  chelicerae5  are  fang-like 
jaws  or  puncturing  bristles,  the  pedipalpi  are  claw-like  or  sheer-shaped,  or 
form  a  suctorial  proboscis/'  The  four  pairs  of  legs  are  usually  well 
developed,  more  rarely  they  are  rudimentary  or  have  partly  vanished  ; 


1  R.  Blanchard  has  compiled  thirty-five  cases  in  which  Myriapoda  have  been 
observed  in  the  intestine  as  well  as  in  the  nose  of  human  beings  ("  Sur  le  pseudo-par 
d.  myriap.  chez  I'homme,"  Arch.  d.  parasit.,  1898,  i.,  p.  452).  E.  Munoz  Ramos  reports 
an  additional  case  (ibid.,  p.  491)  :  A  few  years  ago  a  doctor  in  East  Prussia  sent  me 
a  rain-worm  out  of  a  lady's  nose  (compare  Hanan,  A.,  "  Wahrsch.  Pseudoparas.  v. 
Schweiss  fiiegenlaro.  u.  angebl.  Paras,  v.  Regenwurmern  b.  ein  Hysterisch.,"  Arch.  d. 
paras.,  1899,  ii.,  p.  23). 

a  [This  is  only  so  in  the  Acarina  or  Mites,  not  in  the  Araneida  or  spiders. — F.  V.  T.] 

3  [The  true  character  of  the  Arachnoidea  is  the  presence  of  four  pairs  of  ambulatory 
appendages.     This  number  is  reduced  to  two  pairs  in  the  gall-making  Phytoptidae. — 
F.  V.  T.] 

4  Chelifer  cancroides  has  also  been  observed  as  a  pseudoparasite  in  man  (Arnault 
de  Verey,  S.   "  Pseudopar.  du  chel.  cancr.  chez  I'homme"  (C.  R.  soc.  biol.,   1901,  liii., 
P.  105). 

5  [The  Chelicerae  are  sometimes  regarded  as  modified  antennas,  but  it  is  more  natural 
to  regard  them  as  the  morphological  equivalent  of  the  mandibles  of  Hexapoda. — F.  V.  T.] 

6  [The  pedipalpi  or  second  pair  of  jaws  consist  of  a  stout  basal  joint  and  a  palp, 
which  may  have  the  appearance  of  a  leg  in  Arachnida  ;    this  may  end  with  or  without 
a  claw  or  with  a  chela  (scorpions)  ;    they  may  also  form  a  tube  enclosing  the  styliform 
chelicerse  (mites).— F.  V.  T.] 


LEPTUS  AUTUMNALIS  351 

many  parasitic  forms  are  provided  with  pedunculated  suckers  [ambu- 
lacra, F.  V.  T.].  Respiratory  organs  (tracheal  tufts)  may  be  present  or 
absent.  The  nervous  system  is  reduced  to  a  minimum,  eyes  are  usually 
lacking.  The  intestine,  situated  in  the  central  part,  generally  has  three 
blind  appendages  ;  the  anus  is  situated  on  the  venter  above  the  pos- 
terior end.  Sexes  separated  ;  nearly  all  the  species  deposit  eggs,  from 
which  six-legged  larvae  hatch.  The  acarina  live  either  free  in  the  water 
or  in  moist  soil,  or  they  are  parasitic  on  plants  and  animals.1 


I.     Fam.   Trombidiidce  (Running  Mites). 

Soft-skinned  acarina  with  tracheae  and  with  two  eyes,  usually  peduncu- 
lated ;  they  are  often  brightly  coloured  ;  chelicerae  lancet-  or  claw-  shaped  ; 
pedipalpi  claw-like  ;  legs  composed  of  six  segments,  with  suctorial  discs 
between  the  terminal  ungues.-  Larvae  six-legged. 


Leptus  autumnalis,  Shaw,  1790. 

This  name  is  used  for  the  larvae  of  mites '  which  are  found 
towards  the  end  of  summer  on  grass  plots,  bushes  and  cereals,3 
and  which  have  a  predilection  for  attacking  mammals  and  human 
beings  (Harvest-mites,  Autumn-mites,  Grass-mites,  Rouget,  Bete- 
rouge,  Aoutat,  Red  bug).  To  all  appearances  these  are  the  larvae  of 
at  least  two  species,  the  corresponding  adult  forms  of  which  have 
certainly  long  been  known,  but  have  hitherto  not  been  definitely 
traced  from  these  larvae.  P.  Megnin,  in  1876,  asserted  that 
Leptus  autumnalis  was  the  larval  form  of  Trombidium  holosericeum, 
a  red-coloured  species  of  mite  which  is  frequently  found  on  trees, 
on  the  earth,  &c.,  in  the  spring ;  and  which  in  June  and  July 
deposits  eggs  from  which  reddish  larvae,  0*23  mm.  in  length, 
and  0-19  mm.  in  breadth,  hatch  out.4  As,  however,  Moniez 


1  [Acarina  are  also   found   living  upon  trees  feeding  upon  other  Arthropods  and 
also  upon  spores  of  lichen   and  fungi  (Oribatida  or  Beetle  Mites)  ;    they  also  swarm 
indoors  amongst  stores  and  provisions  (Tyroglyphidce  and  Glyciphagi,  Household,  Sugar 
and  Cheese  mites).— F.  V.  T.] 

2  [Some  have  seven  segments  to  the  legs.— F.  V.  T.] 

3  [This  minute  parasite  is  especially  obnoxious  in  barley  fields.      In  walking  across 
barley  stubble  one  is  sure  to   be  attacked  by  this  parasite  in  the  autumn  in  many 
districts.     This  Leptus  attacks  poultry  also  when  turned  out  on  to  the  stubble  fields 
in  autumn,  but  does  not  do  much  harm. — F.  V.  T.] 

4  [This  mite  occurs  chiefly  in  gardens,  and  is  often  very  prevalent  amongst  rows 
of  peas.     In  the  spring  it  may  frequently  be  found  on  fruit  trees.     In  barley  fields, 
where  Leptus  autumnalis  is  most  abundant,  I  have  often  found  traces  of  Holosericeum 
early  in   the   year.     Nut  pickers  are   frequently  attacked   by  this  Leptus,  and   also 
pickers  in  fruit  plantations. — F.  V.  T.] 


352 


THE    ANIMAL    PARASITES    OF    MAN 


points  out,  the  characteristics  of  these  larvae  do  not  entirely 
correspond  with  those  of  Leptus  autumnalis.  Megnin  has  recently 
found  the  larvae  of  various  Trombidia  on  mammals  and  human 
beings  (1897),  whilst  Brucker  regards  the  larvye  of  Trombidium 
gymnopterum  as  Leptus  (Rouget).  The  old  opinion  which  has 
recently  been  revived  that  Leptus  is  the  larva  of  Tetranychus 
telarius  is  entirely  without  foundation  (von  Hanstein).1 


On  the  skin  of  man  Leptus,  as  a  rule,  produces  itching  and  redness 
(autumnal  erythema);  sometimes  also 
circumscribed  flat  wheals,  the  eruption 
of  which  is  accompanied  by  slight  fever. 
These  symptoms,  however,  disappear 
after  a  few  days.  It  has  been  proved 
that  the  animals  injure  the  skin  and 
plunge  their  long  hypopharynx  into  the 
wound,  which  occasionally  is  situated  at 
the  orifices  of  the  sebaceous  and  sweat 


'/ivy 


FIG.  228. — Leptus  autumnalis,  with  the 
so-called  suctorial  proboscis  (after  Gudclen). 
(Magnified). 


FIG.  229. — Leptus  autumnalis,  100/0. 
The  so-called  proboscis  is  formed 
around  the  hypopharynx  sunk  into 
the  skin.  (After  Trouessart.) 


glands,  in  order  to  suck  up  blood  with  it.  Around  the  stiletto-shaped  hypo- 
pharynx  a  cylindrical  tube,  annularly  thickened  at  the  free  end  (fig.  229),  is 
then  formed  by  the  host  ;  this  has  hitherto  been  regarded  as  the  proboscis  of 
the  Leptus  ;  but  as  a  matter  of  fact  it  belongs  not  to  the  parasite,  but  to 
the  host,  in  the  same  way  as  the  ramified  chitinous  tubules  that  arise  in 
arthropoda  as  consequences  of  the  bite  of  mites  (Flogel,  Trouessart). - 


1  \Tetranychus  telarius  is  well  known  in  all  its  stages  as  a  vegetal  pest.  There 
is  no  connection  in  any  way  between  it  and  the  harvest  bug. — F.  V.  T.] 

-  Kuchenmeister,  F.,  "  Ueb.  d.  sog.  Stachelbeer-oder  Erntemilbe  "  (Varga's  Zeitschr. 
/.  Med.  Chir.  u.  Geburtsh.  N.F.L,"  1862,  i.,  p.  289);  Gruby,  "  Herbstery theme  "  (Attg. 
Wien.  med.  Ztg.,  1861,  p.  19)  ;  Gudden,  "  Ueb.  eine  Jno.  v.  Lept.  aut."  (Arch.  f.  path. 


TROMBIDIUM    TLALSAHUATE  353 

[Leptus  autumnalis  attacks  small  mammals  by  preference,  such 
as  moles  and  hares,  which  are  often  literally  covered  with  them. 
Dogs  are  also  subject  to  their  attack  and  cats  suffer  similarly.  This 
mite  also  frequently  appears  in  colonies  in  cows  ;  cavalry  horses  after 
autumn  manoeuvres  often  suffer  from  an  erythematous  affection 
about  the  hocks  and  knees  due  to  this  pest. 

A  number  of  Leptus,  so  far  undescribed,  occur  abroad  which 
attack  man  in  the  same  way  to  L.  autumnalis  here.  Dr.  Durham 
has  brought  me  specimens  from  British  Guiana  called  Bete  rouge  ; 
these  work  under  the  skin  much  as  does  our  European  species, 
but  it  is  very  distinct,  being  considerably  larger. — F.  V.  T.] 


Trombidium  tlalsahuate  (Lemaire),  1867. 

Trombidium  tlalsahuate  occurs  in  Mexico  under  conditions 
similar  to  those  of  Leptus  here.  It  also  frequently  attacks  men, 
and  by  predilection  fastens  itself  on  to  the  eyelids,  in  the  axillae 
or  navel,  or  on  the  prepuce  ;  it  induces  itching  and  swelling  of 
the  parts  affected,  and  sometimes  even  causes  suppuration  ;  the 
symptoms,  however,  generally  disappear  after  a  week  and  remain 
localised.1 

Other  species  of  mites  which  attack  man  are  reported,  mostly 
by  travellers,  from  various  other  places  ;  zoologically,  however, 
there  is  little  known  about  them.  The  Pou  d' Agouti  in  Guiana, 
Niaibi  in  New  Grenada,  Colorada  in  Cuba,  Mouqui  in  Para, 
represent  a  few  of  these.2 


An.,  1871,  Hi.,  p.  255);  Kramer,  "  Beitr.  z.  Kenntn.  d.  Lepf\  aut."  (ibid.,  1872,  lv., 
p.  354) ;  Megnin,  P.,  "  Mem.  s.  1.  metamorph.  d.  Acariens  "  (Ann.  d.  sc.  nat.  Zool., 
1876  [6],  iv.,  Act.,  No.  5);  Floge),  J.  H.  L.,  "  Ueb.  ein  merkw.  durch  Paras,  hervorger. 
Gewebsneubld."  (Arch.  /.  Naturg.,  1876,  xlii.,  1876,  p.  106) ;  Henking,  H.,  "Beitr. 
z.  An.,  Entw.  u.  Biol.  v.  Tromb.  fulig."  (Z.  /.  w.  Z.,  1882,  xxxvii.,  p.  553);  Megnin,  P., 
"  Les  Acar.  par."  (Encycl.  scientif.  des  aide-mem.,  Paris)  ;  Moniez,  R.,  "  Sur  les  diff. 
Acariens,  qui  s' attach,  d  I'homme  et  qui  ont  recu  le  nom  de  rouget  "  (Rev.  biol.  du  Nord 
de  la  France,  1894-95,  vii.,  p.  301),  Traite  de  parasit.,  Paris,  1896  ;  Brand  is,  F.,  "  Ueb. 
Lept.  aut."  (Fests'hr.  z.  50  jahr.  Besteh.  d.  Prov.  Irrenanst.  Neitleben  bei  Halleyi-  S., 
1897,  P-  4X7)  »  Brucker,  "  Sur  le  rouget  de  I'homme"  (C.  R.  Ac.,  Paris,  1897,  cxxv., 
[2],  p.  879);  Megnin,  P.,  "  Observ.  sur  les  rougets  "  (ibid.,  p.  967);  Thiele,  J.,  "  Die 
Gras-oder  Erntemilbe,  eine  Plage  d.  Feldarh."  (Dtsche.  landw.  Presse,  1898,  No.  98,  p.  1016). 
Trouessart,  E.  L.,  "Sur  la  piqure  du  rouget"  (Arch,  de  paras.,  1899,  ii.,  p.  286); 
Hanstein,  R.  v.,  "  Beitr.  z.  Kenntn.  d.  Gttg.  Tetrany'chus  Duf.  nebst  Bern.  ub.  Lept.  aut." 
(Z.  f.w.  Z.,  1901,  Ixx.,  p.  58). 

1  Lemaire,  "Import,  en  France  du  tlalsahuate"  (C.  R.  Ac.,  Paris,  1867,  Ixv.,  p.  21  0; 
Altamirano,  F.,  and  Duges,  A.,   "  El  tlalsahuate  "  (Fl  estudio,  1892,  iv.,  p.  196) ;    Riley, 
"  The  Mexican  Jigger,  or  tlalsahuate  "  (Insect  Life,  1893,  iv.,  p.  211). 

2  Bonnet,  G.,  "  Contr.  d  V  etude  du  paras"  (These  de  Montpellier,  1870,  No.  IT,  p.  53). 
23 


354 


THE  ANIMAL  PARASITES  OF  MAN 


AKAMUSHI  OR  KEDANI. 

In  a  few  districts  of  Japan  there  occurs  a  serious  illness  (with 
a  mortality  of  40  to  70  per  cent.).  It  is  called  river  or  flood 
fever,  and  the  Japanese  doctors  have  connected  it  with  a  small 
mite  (Akamushi,  JKedani).  Baelz  has  opposed  this  opinion  on  the 
grounds  that  he  has  repeatedly  observed  the  same  species  of  mite 
in  his  dwelling  without  any  subsequent  illness  occurring.  Accord- 
ing to  Keisuke  Tanaka,  however,  a  connection  certainly  does  exist, 


FIG.  230. — The  Kedani  Mite  (enlarged).    (After  Tanaka.) 


inasmuch  as  the  akamushi,  like  Leptus,  attacks  persons  to  suck 
blood.  If  the  mite  is  not  removed,  or  if  the  spot  attacked  is 
injured  by  scratching,  &c.,  a  papule,  surrounded  by  a  red  area 
forms,  and  a  pustule  ensues  ;  and  finally  a  black  scab  covers  .the 
seat  of  injury.  The  lesion  becomes  the  point  of  entrance  of 
bacteria,  especially  a  species  of  PROTEUS  which  produces  river-fever. 
If  the  mites  are  carefully  removed  no  general  illness  takes  place. 
The  orange-red  mites,  which  we  only  -know  in  their  larval 


TETRANYCHUS    MOLESTISSIMUS 


355 


condition,  measure  O'i6 — 0*38  mm.  in  length  by  O'io — 0-24  mm. 
in  breadth.  They  have  leg-like  palpi  with  three  joints,  hirsute 
bodies,  and  very  hairy  legs  composed  of  five  segments  terminating 
with  three  ungues. l 

2.     Fain.  Tetranychidce  (Spinning  Mites). 

These  have  tracheae  and  eyes  ;  the  palpi  are  composed  of  four  segments,  of 
which  the  last  but  one  has  a  powerful  claw  ;  the  antennas  are  two-jointed,  the 
first  joint  solid  and  transformed  into  a  blunt  cone  from  which  the  long,  bent 
stinging  bristle  (the  second  joint)  protrudes.  The  legs  have  six  segments 
with  sucker  discs  between  the  claws. 


Tetranychus  molestissimus,  Weyenbergh,  i886.2 

Found  in  Argentine   and  Uruguay  on  the   under  surface  of   the 
leaves   of  Xanthium  macrocarpum  ;  it   attacks   mammals  and  men, 
producing .  severe     itching,    accom- 
panied by  fever  in  the  latter. 

It  has  been  asserted  by  Haller 
that  the  CAPE  AILMENT  (Port  Natal 
Sickness)  is  caused  by  mites,  but 
this  statement  has  been  contested.3 

2.     Tetranychus  telarius  (L.),  1758 4 
(var.  russeolus,   Koch). 

This  common  spinning  mite  like- 
wise attacks  human  beings,  but 
the  papules  produced  by  it  very 
soon  disappear.  5 


FIG.  231. — Tetranychus  telarius,  var. 
russeolus,  Koch  (enlarged).  (After 
Artault.) 


1  Tanaka,  Keis,  "  Ueb.  JF.t.  u.  Pathog.   d. 
Kedani-Krankh."   (Centr.   f.    Bak.,   Par.    und 
Inf.,  1899  [r],  xxvi.,  p.  432). 

2  [This    species    is    also    known    as   Bicho 
Colorado.      It   spins  a  web   under  the   lower 

surface  of  the  leaves,  and  it  is  only  from  December  to  February  that  it  attacks  warm- 
blooded animals  and  man. — F.  V.  T.] 

8  Haller,  G.,  "  Vorl.  Nachr.  uber  einige  noch  wenige  bekannten  Milben  "  (Zool.  Anzgr., 
1886,  ix.,  p.  52  ;    Fritsch,  G.,  "  Bern.  z.  Herrn  Hatter's  Aufs."  (ibid.,  p.  229). 

4  [There  is  something  wrong  here,  probably  in  the  identification.    T.  telarius  is  purely 
a  plant  feeder,  and  it  is  extremely  unlikely  a  variety  would  attack  man.     Anyhow 
it  will  not  do  so  in  Great  Britain. — F.  V.  T.] 

5  Artault,  L.,  "  Le  platane  et  ses  mefauts  ;   un  nouv.  Acar.  paras,  accid  de  Vhomme  " 
(Arch,  de  paras.,  1900,  hi.,  p.  115). 


356 


THE    ANIMAL    PARASITES    OF    MAN 


3.     Fam.  Tarsonemidce. 

A  family  distinguished  by  complete  sexual  dimorphism,  the  species  of 
which  are  provided  with  tracheae  ;  the  legs  have  five  segments  ;  the  ter- 
minal segments  of  the  front  pair  of  legs  of  both  sexes  possess  a  claw  ; 
the  terminal  segment  of  the  posterior  pair  of  legs  of  the  male  likewise 
has  a  claw.  In  the  female  this  pair  of  legs,  like  the  second  and  third 
pairs  of  both  sexes,  is  provided  with  two  booklets  and  a  sucking  disc. 
The  cuticle  of  the  body  on  the  back  is  "  annulated." 


Pediculoides  ventricosus  (Newport),  1850. 

Syn.  :  Heteropus  ventricosus,  Newport,  1850;  Acarus  tritici,  Lagreze- 
Fossot,  1851  ;  Physogaster  larvarum,  Lichtenstein,  1868  ;  Sphcsrogyna  ven- 
tricosa,  Laboulbene  and  Megnin,  1885. 

Males  are  oval  in  shape,  0*12  mm.  in  length  and  O'o8  mm.  in 
breadth,  flattened.  There  are  six  pairs  of  chitinous  hairs  on  the 


FIG.  232. — Pediculoides   ventricosus.     After   Laboulbene  and    Megnin  (enlarged) — 
a,  male  ;    b,  young  female  ;    c,  gravid  female. 


dorsal  surface  and  a  lyre-shaped  lamella  on  the  posterior  part. 
The  female  in  the  non-gravid  state  is  cylindrical  in  form,  0*2  mm. 
in  length,  and  0*07  mm.  in  breadth  ;  when  gravid  the  posterior 
part  of  the  body  becomes  enlarged  into  a  ball,  which  may  attain 
1-5  mm.  in  size,  as  in  the  case  of  Pulex  penetrans,  and  of  the  female 
Termites.  On  emerging  the  young  are  already  provided  with  four 
pairs  of  legs  and  copulate  soon  after  birth. 


TYDEUS    MOLESTUS 


357 


These  animals  live  on  the  stalks  of  cereals,  and  feed  on  vegetable  and 
animal  juices  ;  they  are  therefore  also  found  on  corn-infesting  insects.  They 
invade  the  barns  and  seek  out  the  insects  living  in  the  dry  grains  of 
corn,  or  wait  for  an  opportunity  of  obtaining  food.  They  have  been 
repeatedly  observed  on  human  beings,  particularly  labourers  occupied  in 
handling  grain  ;  their  bite  causes  severe  irritation,  local  elevation  and 
reddening  of  the  epidermis,  as  well  as  fever.  It  cannot  be  positively 
asserted  that  all  cases  of  the  occurrence  of  cereal  mites  on  man  relate  to 
Pediculoides  ventricosus,  as  the  descriptions  are  often  insufficient.  Geber 
states  that  one  form  is  Chrithoptes  monunguiculosus ,  cr  A  cams  hordei  ; 
Flemming  mentions  Tarsonemus  uncinatus  ;  Roller  Oribates  sp.,  and  Karpelles 
Tarsonemus  intectus.1 


4.     Fam.  Eupodidce. 

Small  tracheate  mites,  with  moderately  long  or 
short  pedipalpi,  composed  of  four  segments,  of 
which  the  last  segments  bend ;  chelicerae  forceps- 
shaped,  with  serrated  edge  ;  legs  with  two  claws, 
more  rarely  with  one,  and  terminating  in  a  tuft 
ornamented  with  fine  hairs  ;  genital  orifices  on  the 
abdomen,  surrounded  by  a  circle  of  little  hairs. 
Most  species  live  free,  one  lives  parasitically  on  the 
bodies  of  slugs. 

Tydeus  molestus,  Moniez,  1889. 

Male,  0*2  mm.  in  length,  0*125  in  breadth. 
Females,  0*225  mm-  m  length,  0-135  in 
breadth ;  gravid  female  0*315 — 0*360  mm.  in 
length  and  0*180  mm.  in  breadth.  They 
were  observed  by  Moniez  on  an  estate  in  FlG-  233.— Tydeus  moles 

_        .  \  tus  seen  m  profile,  enlarged. 

Belgium,  whither  the  creature  had  apparently  (After  Moniez.) 

been   imported   twenty-five   years   previously 

with    Peruvian    guano ;    they   appeared    regularly   in    the    summer 

and    remained    until    the   first   frost  set  iii ;   they  were   found  on 


1  Lagreze-Fossot,  A.,  and  Montane,  R.  J.  (Rec.  agronom.  soc.  d.  sc.,  agric.  et  belles 
lettres  du  dep.  de  Tarn  et  Garonne,  1851,  xxxii.,  No.  2) ;  Robin,  Ch.,  and  Rouyer,  "  Erupt, 
cutanee  due  d  V  A  cans  du  ble  "  (C.  R.  soc.  biol.,  1867,  iv.,  p.  178);  Laboulbene,  A., 
and  Megnin,  P.,  "  Mem.  sur  le  Sphtzrogyna  ventricosa  "  (Journ.  de  Vanat.,  1885,  xxi., 
p.  i)  ;  Geber,  E.,  "  Entzundl.  Processe  der  Haut  durch  ein  bis  j'ctzt  nicht  bestimmte 
Milbe  veranlasst  "  (Wien.  med.  Presse,  1879,  xx.)  ;  Roller,  Jr  (Pest.  med.  chir  Presse, 
1882,  No.  36,  and  Biol.  Centralbl.;  1885,  iii.,  p.  127);  Rarpelles,  L.,  "  Ein  auf  den 
Mensch  u.  auf  Getreide  lebende  Milbe"  (Anz.  d.  K.  K.  Acad.  d.  Wiss.,  Wien.,  1885, 
xxii.,  p.  160,  and  Centralb.  f.  Bakt.  u.  Paras.,  1887,  i.,  p.  428);  Flemming,  J.,  "  Ueber 
eine  geschlechtsreife  Form  der  als  Tarsonemus  beschriebenen  Thieve  "  (Zeitschr.  /.  d. 
ges.  Naturwiss.,  Halle,  1884,  iii.,  p.  472)  ;  Rramer,  "  Zu  Tarsonemus  uncinatus  Flem." 
(ibid.,  p.  671)  ;  Moniez,  R.  "  Sur  I' habit,  normal,  dans  Us  tiges  d.  cereales,  d'un  paras, 
dccid.  de  I'homme  "  (Rev.  biol.  duNord  de  la  France,  1895,  vii.,  p.  148  ;  Traite  de  Paras., 
Paris,  1896). 


THE    ANIMAL    PARASITES    OF    MAN 


grass  plots,  on  trees  and  bushes  in  masses  ;  they  regularly  at- 
tacked persons,  mammals  and  birds,  tormenting  their  hosts  in  a 
terrible  manner.1 


5.     Fam.  Gamasidcz  (Coleopterous  mites). 

Chelicerae  sheer-like  or  piercing  ;  pedipalpi  filiform  ;  the  legs  are  com- 
posed of  six  segments  with  two  terminal  ungues  and  a  bladder-like  sucking 
disc  [caruncle,  F.  V.  T.].  Stigmata  situated  between  the  third  and  fourth 
pairs  of  legs  ;  the  cuticle  thickened,  leather-like,  no  eyes  ;  the  larvae  have 
six  legs. 

Dermanyssus  gallince.  (de  Geer),   1778. 

Syn.  :  Pulex  gallincB,  Redi,   1674  ;  Acarus  gallince,  de  Geer,   1778  ; 
Dermanyssus  avium,  Duges,   1834. 

The  male  measures  0*6  mm.  in  length  by  0*32  mm.  in  breadth  ; 
the  female  07 — 075  mm.  in  length  by  0-4  mm.  in  breadth.  The 
body  is  somewhat  pear-shaped ;  the  colour  whitish,  reddish,  or  red- 
dish-black, according  to  the  contents  of  the  intestine.  The  legs  are 
fairly  short  and  strong.  During  the  day  they  live  concealed  in 
the  nests,  cracks,  &c.,  of  the  hen-house,  and  at  night  attack  the 
inmates  in  order  to  suck  their  blood  ;  they  rarely  remain  long  on 
the  birds.  They  have  been  repeatedly  found  on  persons,  on 
whose  skin  they  produce  an  itching  eruption.2 


Dermanyssus  hirundinis  (Hermann),  1804. 
Syn.  :   Acarus   hirundinis ,   Herm.,  1804. 

Of  a  brownish- violet  colour,  1*2  or  1*4  mm.  in  length  ;  lives 
in  the  nest  of  swallows  and  is  occasionally  found  on  man.3 

[The  Red  Hen  Mite  (Dermanyssus  gallina)  not  only  attacks 
poultry  and  man,  as  stated  above,  but  is  found  on  all  birds  and 


1  Moniez,  R.,  Les  Paras,    de    I'homme,  Paris,  1889,  p.  129;   "Hist.  nat.  du  Tydeus 
molestus."  (Rev.  biol.  Nord  de  la  France,  1893-94,  vi.,  p.  419). 

2  Alt,  Ch.  H.,  De    phthiriasi.  Diss.  in.  Bonnce,   1824;    Simon,  G.,  Die  Hautkrkh. 
durch  anat.  Unters.  erl.,  2nd  edit.,  Berlin,  1851,  p.  320;    Itzigsohn,  H.,  "  Pathol.  Bas,a- 
tellen.   /.   Psora  dermanyssica"    (Virchow's  Arch.,    1858,   xv.,   p.    166) ;    Judee,    "  Sur 
un  nouveau  paras,  de  la  peau  chez  I'homme  "  (C.  R.  soc.  biol.,  Paris,  1867,  iv.,  p.  73)  ; 
Wagner,  A.,  Ueb.  d.   York.   v.  Derman.  avium  b.  Mensch.  In.  Disc.   Greifswald,  1873  ; 
Geber,  E.,  In  Ziemssen's  Handb.  d.  spec.  Path.  u.  Ther.,  1884,  xiv.  [2],  p.  394)  ;    Blan- 
chard,  R.,  "  Not  sur  les  par.  de  I'homme.  2  Ser.  II.  Nouv.  cas  de  Derm,  gallince  dans 
I'esp.  hum."  (C.  R.  soc.  biol.,  Paris  [10],  1894,  i.,  p.  460). 

3  Die  Cartenlaube,  1863,  p.  23. 


HOLOTHYRUS    COCCINELLA 


359 


many  mammals.  The  Dermanyssus  gallince  is  the  same  as  D 
avium.  The  species  found  in  swallows'  nests  is  also  said  to  be 
the  same.  This  mite  can  remain  for  weeks  without  any  food 
from  its  normal  host.  They  only  attack  man  when  entering  or 
cleaning  dirty  and  neglected  fowl  houses ;  upon  him  they  do  not 
produce  a  true  dermatosis.  They  chiefly  attack  the  back  of  the 
hands  and  forearms  of  those  who  constantly  attend  poultry  and 
give  rise  to  symptoms  similar  to  the  papular  eczema  of  scabies. 
That  they  may  remain  some  time  upon  the  human  body  we  know 


FIG.  234. — Dermanyssus  gallinat 
(enlarged).     (After  Berlese.) 


FIG.  235. — Dermanyssus  hirundinis. 
40/1.     (After  Delaforid.) 


from  the  following  cases  out  of  many  recorded  :— Geber  observed 
that  the  Dermanyssus  had  caused  a  diffused  eczema  on  a  woman, 
which  lasted  four  weeks  and  then  disappeared.  The  Tique  of  F.  Y. 
Raspail  is  the  bird  Dermanyssus  ;  he  records  children  and  adults 
being  attacked  not  only  when  handling  pigeons,  but  even  when 
walking  in  a  garden  manured  with  pigeons'  dung.  The  affection 
soon  disappeared  when  the  pigeons  were  destroyed  and  the  excreta 
buried,  I  have  frequently  heard  of  poultrymen  being  seriously 
attacked  by  this  pest.— F.  V.  T.] 

Holothyrus  coccinella,  Gervais,  1642. 

Measures  5  mm.  in  size  ;  lives  on  birds  in  the  island  of  Mauritius  ; 
ducks  and  geese  frequently  fall  victims  to  its  bite ;  it  also 
attacks  human  beings,  on  whose  skin  it  causes  severe  burning 
and  swelling,  but  no  reddening ;  it  may  be  dangerous  to  chil- 
dren, especially  by  settling  in  the  oral  cavity.1 

'  Gervais,  P.,  "  15  esp.  d.  Insect,   apt."  (Ann.  soc.  ent     France,  1842,  xi     p.  14) •  ; 
Megnin,  R,    "  Un  acarien  dan<>ereux  de  Vile  Maurice  "  (C.  R.  soc.  biol.,  F 
v.,  p.  251). 


366  THE    ANIMAL    PARASITES    OF    MAN 

6.     Fam.  Ixodidcz  (Ticks).1 

Comparatively  large  acarines  with  a  leathery  skin  ;  they  are  flattened 
in  form,  but  after  sucking  blood  the  abdomen  becomes  spherical  ;  the 
chelicerae  are  rod-like  and  possess  a  serrated  terminal  joint,  bent  hook- 
like  ;  the  median  parts  of  the  pedipalpi  (maxillae)  form  a  rostrum  fur- 
nished with  barbed  hooks  (fig.  236)  ;  the  maxillary  palpi  themselves  are 
club-like  or  rounded  ;  the  legs  are  composed  of  six  segments  with  two 
terminal  ungues  ;  often  also  with  "  sucking-discs  "  ;  the  stigmata  are  at  the 
sides  of  the  body,  posterior  to  the  fourth  pair  of  legs.  The  larvae  are 
six-legged. 

[The  true  ticks  (Ixodidce)  are  all  blood-suckers,  and  as  far  as  is 
known  they  do  not  take  vegetable  food  at  all.  Not  only  are  the 
Ixodidce  important  as  actual  parasites,  but  they  are  most  so  on 
account  of  the  fact  that  they  are  the  active  agents  in  carrying 
various  diseases  in  animals  and  apparently  in  man.  It  has  been 
conclusively  proved  that  the  Bont  tick  (Amblyomma  hebrceum)  is 
the  carrier  of  the  fatal  "  heart-water  fever  "  so  rife  amongst  sheep  in 
South  Africa,  that  the  dog  tick  (Hcemapsyllis  leachi)  is  the  agent  by 
which  the  protozoa  that  cause  malignant  jaundice  in  dogs  is  dis- 
tributed, that  Texas  fever  in  cattle  is  spread  by  Rhipicephalus 
annulatus,  and  Coast  or  Rhodesian  fever  by  R.  appendiculatus  and 
R.  Simus.  Their  importance  as  disease  carriers  amongst  mammals 
is  therefore  considerable,  and  it  may  prove  to  be  so  for  man.2 
They  frequently  attack  man  (vide  p.  368)  ;  but  chiefly,  according  to 
my  observations,  in  their  early  stages  in  Europe  ;  this  is  not  so,  how- 
ever, abroad  (vide. p.  373).  The  life-history  of  a  number  of  ticks  has 
been  clearly  demonstrated.  Mr.  Wheler  has  shown  that  in  Ixodes 
reduvius  it  is  as  follows.  The  female  deposits  her  eggs  in  masses  upon 
the  ground,  and  then  gradually  reducing  in  size  as  the  eggs  pass  out 
until  she  finally  remains  a  mere  shrivelled  empty  bag  and  then  dies. 
The  eggs  are  oval,  golden-brown  in  colour  and  smooth  ;  in  length 
they  are  0*59  mm.  ;  as  in  all  Ixodidae  they  are  covered  with  a 
glutinous  secretion,  by  means  of  which  they  adhere  together  in 
masses.  These  egg  masses  may  be  deposited  anywhere  on  the 
ground,  but  amongst  rough  coarse  herbage  seems  to  be  the  favourite 
place.  The  egg  stage  may  last  as  long  as  twenty-two  weeks,  or  it 

1  Pagenstecher,    H.    A.,  Beitr.  z.  Anat.  d.  Milben.,   1861,  ii.,  Lpz.  ;    Bertkau,  Ph. 
"  Bruchstucke  -a.  d.  Lebensgeschichte  unserer  /ecke"  (Verh.  d.  nat.   Ver.  d.  pr.  Rheinl. 
u.  West/.,  Stzgsber.,  1881,  p.  145)  ;  Johannessen,  A.,  "Acute  Polyurie  bei  einem  Kinde 
nach  dent  Stiche  eines  Ix.  ric."  (Arch.  /.  Kinderhlkde.,  1885,  vi.,  p.  337)  ;  Blanchard,  R., 
"  Penelr.  de  I'lx.  ric.  sous  la  pcau  de  I'homme  "  (C.  R.  soc.  bioL.  1891  [9],  p.  689)  ;  Neu- 
mann, G.,  "  Revis.  de  la  fam.  des  Ixodides  III."  (Mem.   soc.   zooL,  France,  1899,  xii., 
p.  107). 

2  This  has  been  recently  proved  in  Uganda — so  called  tick  fever  in 


IXODID.E  361 

may  only  take  eight  weeks.  In  the  case  of  the  Bont  tick  a  single 
female  will  deposit  15,000  or  more  eggs.  The  process  of  egg-laying 
is  described  as  follows  by  Mr.  Wheler  :  "  When  egg-laying  is  about 
to"  take  place,  the  head  is  further  depressed  till  it  rests  close  against 
the  under  side  of  the  body.  In  this  attitude  the  end  of  the  rostrum 
actually  touches  the  genital  orifice,  the  palpi  being  at  the  same 
time  widely  opened  out.  Behind  the  head  and  from  beneath  the 
shield  at  what  for  the  purposes  of  explanation  may  be  described 
as  the  back  of  the  neck,  a  white,  perfectly  transparent,  delicate 
gelatinous  membrane  is  brought  down  through  inflation,  either  with 
air  or  with  a  transparent  fluid,  above  the  head,  which  it  temporarily 
conceals.  The  end  of  this  membrane  terminates  m  two  conical 
points  which  appear  to  be  covered  with  a  glutinous  secretion,  and 
at  the  same  time  an  ovipositor  of  a  somewhat  similar  character, 
but  only  semi-transparent,  is  pushed  forward  from  the  genital 
orifice.  This  latter  is  a  tube,  within  which  is  the  egg.  As  the 
ovipositor  projects  it  turns  itself  inside  out,  like  the  finger  of  a 
glove,  leaving  the  egg  protruded  at  the  end  and  lying  between  the 
two  finger-like  points  of  the  membrane.  The  membrane  and  the 
ovipositor  are  then  withdrawn  each  from  the  other.  The  egg 
adheres  to  the  former,  which  collapses  through  the  withdrawal  of 
its  contents,  dragging  the  egg  forward  and  depositing  it  on  the  top 
of  the  head.  Neither  legs,  palpi,  nor  the  organs  of  the  mouth  take 
any  part  in  oviposition,  but  after  the  collapse  of  the  membrane  the 
palpi  are  closed  and  the  head  i^  raised,  by  which  action  the  egg  is 
pushed  forward  to  the  front  edge  of  the  shield,  forming  in  time  an 
adherent  mass  of  eggs,  which  are  deposited  in  front  of  the  tick." 

The  egg  gives  rise  to  the  larval  form,  the  so-called  "  seed-tick  " 
stage.  At  first  these  minute  specks  are  pallid  and  soft,  but  they 
soon  harden  and  darken  in  colour.  These  larvae  are  six-legged  and 
soon  crawl  up  grasses  and  various  plants,  and  there  await  a  passing 
host,  waving  their  two  front  legs  in  the  air  and  becoming  attached 
by  this  means.  The  larval  ticks  feed  upon  the  blood  of  the  host, 
and  when  repleted  fall  to  the  ground,  the  body  becoming  inflated  in 
the  meanwhile.  These  larvae  may  remain  on  the  host  only  two 
days,  or  they  may  remain  much  longer.  Eventually  they  moult  on 
the  ground,  and  change  to  the  nymph  or  pupal  stage,  which  has 
four  pairs  of  legs.  This  pupa  acts  just  as  the  larva,  crawls  up 
plants  and  waits  to  regain  the  host.  After  a  time  the  nymphs, 
having  gorged  themselves  with  blood,  fall  off  and  remain  on  the 
ground  for  nearly  three  months  ;  they  then  moult  and  become  adult 
males  and  females.  In  about  ten  days  they  assume  their  normal 


362  THE    ANIMAL   PARASITES    OF   MAN 

colour  and  regain  the  host  afresh  ;  the  female  gradually  swells  until 
she  attains  that  large  inflated  form  so  characteristic  of  ticks.  The 
male  does  not  swell,  but  nevertheless  feeds  upon  the  host  and 
fertilises  the  female. 

The  act  of  coitus  is  strange,  the  male  tick  inserts  its  rostrum  and 
other  mouth  organs  into  the  sexual  orifice  of  the  female,  between  the 
base  of  the  posterior  pair  of  legs.  The  males  then  die  and  the  females 
fall  to  the  ground  and  deposit  the  ova.  There  are  variations  in  the 
different  species,  of  course,  from  those  given  above,  which  apply 
solely  to  Ixodes  reduvius.  The  larvae  and  nymphs  seem  to  attack 
most  animals,  but  the  adults  mainly  keep  to  the  same  host.  The 
periods  in  the  life  cycle  of  ticks  not  only  vary  in  the  different 
species  but  in  each  species  according  to  climatic  conditions.  For 
instance,  in  the  Bont  tick  (Amblyomma  hebr&um,  Koch),  Lounsbury 
has  shown  that  the  development  is  rapid  in  summer,  slow  in  winter. 
The  period  from  the  time  that  the  female  drops  to  the  time  she 
commences  to  lay  eggs  varied  in  specimens  observed  by  him  from 
twelve  days  in  summer  to  twelve  weeks  in  winter,  and  the  complete 
period  from  the  dropping  of  the  female  to  the  hatching  of  the  eggs, 
from  eleven  weeks  in  summer  to  thirty-six  weeks  through  the  winter. 
Other  stages  vary  in  a  similar  manner. 

Ticks  may  live  a  long  time  away  from  the  host  provided  they  are 
supplied  with  a  certain  amount  of  moisture.  Mr.  Wheler  kept  dog 
ticks  (Ixodes  plumbeus)  in  the  larval  stage  for  ten  months.  The 
pupae,  male  and  female,  of  Ixodes  rqduvius  for  six  months. 

In  many  species  moulting  takes  place  off  the  host,  but  in  Ixodes 
bovis,  now  known  as  Rhipicephalus  annulatus,  Say  (the  carrier  of 
Texas  fever),  moulting  takes  place  on  the  host,  and  in  many  other 
species  also.1  Some  species  of  ticks  leave  their  host  on  its  death 
(as  the  dog  tick,  Hcemaphysalis  Leachi),  but  others  die  with  the 
host  (Bont  Tick,  Amblyomma  hebrceum). 

CLASSIFICATION  OF  IXODID^:. 

The  TICKS,  or  Ixodidce,  are  divided  into  two  groups,  known  as 
(i)  Argasinae,  (2)  Ixodinae.  The  Argasince  are  told  from  the  Ixodinae 
by  the  absence  of  dorsal  or  ventral  shields  in  both  sexes,  and  also 
by  the  rostrum  being  placed  beneath  the  cephalo-thorax,  which 
covers  it  over,  except  in  the  larval  stage,  in  which  it  is  terminal,  and 
in  the  pupal,  when  it  partly  projects.  Legs  nearly  equal  in  length. 
The  sexual  orifice  is  situated  between  the  two  first  pairs  of  legs. 
The  males  usually  smaller  than  the  females. 

1  Some  Ticks  require  only  one  (R.  decolor  atus]  others  two  (R.  evertsi)  and  some 
three  hoats  (R.  appendiculatus)  in  order  to  reach  maturity. 


IXODID.E  :    SYNOPSIS    OF    GENERA  363 

The  Ixodina  have  the  legs  unequal,  of  six  segments  with  two 
false  segments,  making  them  look  as  if  composed  of  eight  segments. 
The  rostrum  is  terminal  and  never  hidden  beneath  the  body.  The 
sexual  orifice  is  situated  between  the  haunches  of  the  first  three 
pairs  of  legs.  In  the  males  the  orifice  is  obsolete  or  very  rudi- 
mentary ;  sexual  intercourse  being  effected  by  the  rostrum.  The 
males  are  smaller  than  the  females.  The  shield  in  the  females  never 
covers  so  much  as  one  half  of  the  body  even  when  fasting,  also 
in  the  larvae  and  nymphs  ;  but  in  the  males,  which  do  not  distend, 
the  shield  covers  the  body  entirely,  or  all  but  a  narrow  margin. 
The  Ixodinae  are  divided  into  two  groups  :  (i)  the  Ixo&ce  .and  (2)  the 
Rhipicephalce.  The  former  have  a  long  proboscis  reaching  nearly  to 
the  end  of  the  palpi  or  even  a  little  longer  than  the  palpi.  The 
palpi  are  longer  than  broad.  The  Rhipicephalcz  have  short  palpi, 
nearly  or  quite  as  broad  as  long,  more  or  less  conical  or  subtriangular. 
They  were  called  Conipalpi  by  Canestrini. 

SYNOPSIS  OF  GENERA. 

A.  Rostrum  concealed  in  adult,  partly  exposed  in  larvae  and 

nymphs.     No  dorsal  and  ventral  shields. 

Body  flat  with  thin  edges,  finely  shagreened  and  punctate  .     Argas. 
Body  with  numerous  small  round  granules  and  with  thick 

sides Ornithodorus. 

B.  Rostrum   terminal.     Body  with  dorsal  shield  over  some 

part  of  it. 

I.  Rostrum  and  palpi  longer  than  broad  (Ixodince}. 

a.  A  groove  around  anus  in  front.     Palpi  caniculated  in 

both  sexes .     .     .     . Ixodes. 

Palpi  claviform,  not   caniculated  in   the  male ;   legs 
very  long Escatocephahis . 

Palpi    claviform,  not  caniculated  in  the  male  ;   anal 

groove  absent  in  the  female Ceratixodes. 

j8.  A  groove  around  the  anus  behind. 

No  eyes  ;  ad -anal  shields Aponomma. 

Eyes  present. 

Males  with  no  ad-anal  shields Amblyomma. 

Males  with  ad-anal  shields Hyalomma 

II.  Labium  and  palpi  short ;  palpi  not,  or  very  little,  longer 

than  broad  (Rhipicephala) . 
a.  No  eyes. 

Rostrum  rectangular  ;  no  ventral  shields  in  the  male  .     H&maphysalis. 
0.  Eyes  present. 

Rostrum   with   salient    angles ;   either    two    or    four 

shields  at  the  side  of  the  anus  in  the  male      .     .     .     Rhipicephalus. 
Rostrum  rectangular.    No  ad-anal  shields  in  the  male, 
but  usually  with  greatly-developed  coxae  on  fourth 
pair  of  legs Dermacentor. 


364  THE   ANIMAL   PARASITES   OF   MAN 

The  genus  Ceratixodes  of  Neumann  (1902)  occurs  on  birds. 
The  genus  Eschatocephalus  of  Frauenfeld  (1853),  of  which  seven  species  are 
known,  are  mostly  parasitic  on  bats,  and  are  found  in  holes,  caves  and  church 
towers. 

The  genus  Apqnomma  of   Neumann   (1899)  is  exotic,  and  almost  entirely 
confined  to  snakes  and  saurians. 

The  following  are  synonyms  of  the  different  genera  : — 
Argas,  Latreille,  1796  (Rhynchoprion ,  Hermann,  1804). 
Ixodes,  Latreille,  1795  (Acarus,  Linnaeus,  1758;  Cynorhcestes,  Hermann,  1804; 

Crotonus,  Dumeril,  1822). 
Ceratixodes,  Neumann,  1902  (Ixodes,  Cambridge,  1879  ;  Hyalomma,  Cambridge, 

1879). 

Eschatocephalus,  Frauenfeld,  1853  (Sarconyssus,  Kolenati,  1857). 
Amblyomma,  Koch,  1844  (Ixodes,  Latreille,  1795). 
Htemaphysalis,  Koch,  1844  (Rhipistoma,  Koch,  1844;  Gonixodes,  Duges,  1888  ; 

Opitodon,  Canes trini,  1897). 
Rhipicephalus ,  Koch,   1844  (Acarus,  Linnaeus,  1758  ;   Ixodes,  Latreille,  1795  ; 

Phanloixodes,  Berlese,  1889  ;  Boophilus,  Curtice,  1890). 

Dermacentor,  Koch,  1844  (Ixodes,  Latreille,  1795  ;  Pseudixodes,  Haller,  1882). 

— F.  V.  T.] 


Ixodes  reduvius  (L.),  1758. * 
Syn.  :  Acarus  reduvius  and  ricinus,  L.  ;  Ixodes  ricinus,  Latreille,   1806. 

The»males  are  oval ;  their  length  i'2 — 2  mm.  ;  they  are  brownish- 
red  or  black  in  colour ;  the  females  are  yellowish-red,  4  mm. 
long  ;  when  gorged  they  are  lead-coloured  and  may  attain  12  mm. 
in  length  by  6 — 7  mm.  in  breadth. 

The  dog  tick  (fig.  237)  lives  in  thickets  on  leaves,  &c.,  and  attacks  sheep 
and  oxen,  and  more  rarely  dogs,  horses  and  human  beings,  into  the  skin 
of  which  the  female  bores  with  the  rostrum  in  order  to  suck  blood ;  the  bite 
is  not  dangerous  and  sometimes  is  not  even  felt.  Inflammation,  however, 
is  set  up  if  the  creatures  are  forcibly  removed  from  the  wound,  as  the 
rostrum  as  a  rule  is  torn  off  in  the  process.  If  left  alone  or  smeared  over 
with  some  grease — vaseline,  oil,  butter,  &c. — the  creatures  drop  off  sponta- 
neously. Sometimes  the  entire  tick  bores  itself  into  the  skin  ;  they  also 
appear  to  be  permanent  inmates  of  kennels. 

[The  species  (Ixodes  reduvius)  is  the  same  as  Ixodes  ricimis, 
Latreille.  The  male  is  2*35 — 2*80  mm.  long  ;  the  body  is  dark  brown, 
almost  black,  with  a  pale  almost  white  margin  ;  there  are  also  traces 
of  reddish  mottling.  Coxae  of  the  first  pair  of  legs  with  a  short 
spine.  Rostrum  much  shorter  than  that  of  the  female  ;  shield 

1  Ixodes  reduvius  and  /.  ricinus  are  synonymous.  [The  above  should  read  Ixodes 
ricinus,  Latreille,  1804.— F.  V.  T.] 


IXODES    REDUVIUS 


365 


oval ;  anal  shield  small,  about  one-third  the  length  of  ventral  shield. 
The  adult  female  varies  from  2*80 — 3*5  mm.  when  not  distended,  but 
when  gorged  may  reach  10  mm.  long.  The  shield  and  legs  are 
dark  blackish-brown,  body  deep  orange-red  with  four  dark  longi- 
tudinal lines,  paler  beneath  and  light  grey  in  front.  When  dis- 
tending it  is  pale  red  to  grey  or  white  ;  when  fully  gorged  olive-green, 
or  dark  red  to  black  with  irregular  yellow  streaks  on  the  back  and 
sides  just  before  egg  laying.  Sexual  orifice  opposite  fourth  pair  of 
legs.  The  pupa  varies  from  i'6o — 1*70  mm.  long  when  fasting  ; 
the  body  is  olive-white,  opaque,  with  four  distinct  brown  posterior 
markings  and  similar  anterior  ones,  leaving  a  pale  centre  to  the 
shield.  When  fully  gorged  it  is  3  mm.  long.  As  the  pupa  distends 
it  changes  from  opaque  white  to  blue-black  and  finally  black.  The 


B. 


FIG.  236. — A,  the  rostrum  of  Ixodes 
ricinus  (male)  ;  B,  the  terminal  joint 
of  the  maxillary  palpi  of  the  female 
(enlarged).  (After  Pagen steelier.) 


FIG.  237. — Female  of  Ixodes  ricinus, 
gorged  full,  ventral  and  dorsal  surfaces. 
2/1.  (After  Pagenstecher.) 


little  larva  is  0*80 — 1*50  _mm.  long,  transparent  with  olive-green 
intestinal  markings  ;  as  it  becomes  inflated  it  changes  to  blue- 
black  and  then  black.  They  have  no  eyes.  It  is  widely  distributed 
and  chiefly  attacks  sheep  ;  sometimes  it  occurs  on  dogs  and  also 
attacks  man.  Megnin  records  it  from  horses  in  the  nymph  stage. 
Amongst  its  other  numerous  hosts  are  goats,  cattle,  deer,  hedgehogs, 
moles,  bats,  birds  and  lizards.  It  is  usually  known  as  the  Grass 
Tick  and  Bottle-nosed  Tick. 

Synonyms. — Considerable  confusion  exists  over  the  name  of  this 
and  other  common  Ticks,  owing  to  the  same  species  having  been 
described  under  a  great  many  names.  Observers  have  taken  the 
same  species  on  different  animals  and  in  various  stages  to  be  distinct 
and  have  described  them  accordingly. 

The  name  Ixodes  reduvius,  Leach,  does  not  stand,  as  Leach  was 


366  THE    ANIMAL   PARASITES    OF    MAN 

describing   quite   a  different    parasite.      The    name    Ixodes    ricinus, 
Latreille,  1804,  is  now  substituted  by  Neumann  and  Wheler. 

The  synonyms  given  by  Wheler  are  as  follows  :  Reduvius, 
Charleton,  1668  ;  Ricinus  caninus,  Ray,  1710  ;  Acarus  ricinoides, 
De  Geer,  1778  ;  Acarus  ricinus,  Linnaeus,  1788  ;  Cynorhcestes  reduvius, 
Hermann.  1804  ;  C.  ricinus,  Hermann,  1804  ;  Ixodes  megathyreus, 
Leach,  1815  ;  Ixodes  bipunctalus,  Risso,  1826  ;  Cynorhcestes  hermanni, 
Risso,  1826;  Crotonus  ricinus,  Dumeril,  1829;  Ixodes  trabeatus, 
Audouin,  1832  ;  T.  plumbeus,  Duges,  1834 ;  I.  reduvius,  Hahn,  1834 ; 
/.  fuscus,  Koch,  1835  (?) ;  T.  lacericz,  Koch,  1835  (?) ;  T.  pustularum, 
Lucas,  1866 ;  /.  fodiens,  Murray,  1877 ;  /.  rufus,  I.  sulcatus,  and 
I.  sciuri,  Koch. — F.  V.  T.] 

Ixodes  hexagonus,  Leach  (1815). 
Syn'.  :    Ixodes  sexpunctatus ,  Koch,  1897  ;  Ix.  vulpis,  Pagenstecher,  1861. 

Lives  in  the  same  manner  as  the  foregoing  ;  has  a  predilection 
for  attacking  hunting  dogs,  but  does  not  spare  other  mammals  or 
even  birds.  The  difference  consists  in  the  shape  of  the  legs,  the 
shorter  rostrum,  and  the  larger  size  of  the  male.  It  also  occa- 
sionally attacks  man,  but  is  usually  confused  with  the  previously 
mentioned  species.1 

[The  synonyms  of  this  species  are  as  follows  : — Ixodes  autumnalis, 
Leach,  1815;  Ixodes  erinacei,  Audouin,  1832;  Ixodes  reduvius, 
Audouin,  1832  ;  Ixodes  crenulatus,  Koch ;  Ixodes  erinxceus,  Murray, 
1877 ;  Ixodes  ricinus,  Megnin,  1880.  Two  other  synonyms  are  given 
above  by  Braun. 

The  female  when  fully  replete  is  n  mm.  long,  when  fasting 
3' 86  mm  ;  the  shield  is  heart-shaped  and  punctate,  body  finely  hair$  ; 
palpi  short  and  broad ;  labium  shorter,  and  tarsi  of  all  the  legs  more 
truncate  than  in  Ixodes  ricinus.  The  colour  of  the  distended  body 
is  drab  and  somewhat  waxy  ;  rostrum,  shield  and  legs  light  testa- 
ceous. The  male  varies  from  3*5 — 4^0  mm.  long,  and  is  reddish- 
brown  in  colour  with  lighter  legs  ;  the  shield  is  punctate  and  leaves 
a  narrow  margin  around  the  body  ;  the  body  is  elliptical,  almost  as 
large  in  front  as  behind.  There  is  a  spine  on  the  coxae  of  the  first 
pair  of  legs,  which  is  shorter  than  in  the  male  /.  ricinus  and  longer 
than  in  the  female.  The  genital  orifice  is  opposite  the  interval 
between  the  second  and  third  pair  of  legs.  The  fasting  nymph  is 

1  Neumann,  G.  L.,  cf.  p.  129. 


AMBLYOMMA  CAYENNENSE  367 

1-76  mm.  long,  light  bluish-grey,  margined  and  transparent,  with 
four  large  posterior  intestinal  marks  joined  together  behind  the 
shield  and  smaller  ones  extending  to  the  front  and  sides.  When 
fully  distended  it  is  uniformly  brownish-white  ;  shield,  legs  and 
rostrum  pale  testaceous.  The  larva  varies  from  o-88  mm,  when 
fasting  to  1*76  mm.  when  gorged.  Its  body  is  light,  but  gradually 
becomes  darker,  with  similar  intestinal  marks  to  ricinus. 

This  tick  is  very  common,  especially  on  ferrets,  stoats  and  hedge- 
hogs. It  is  also  found  on  sheep,  cattle,  &c.  The  males  do  not 
generally  occur  in  company  with  the  females  on  the  host.  Pairing 
probably  takes  place  on  the  ground. — F.  V.  T.] 

Amblyomma  cayennense,  Koch,  1844. 

Syn.  :  Amblyomma  mixtum,  Koch,  1844  ;  Ixodes  herrerce,  Duges,  1887  ; 
Amblyomma  sculptum,  Berlese,  1888. 

Characterised  by  the  possession  of  eyes.  The  male  measures 
3' 8  mm  in  length  by  3  mm.  in  breadth  ;  the  female '4  mm.  in  length 
by  3  mm.  in  breadth,  but  when  full  of  blood  may  become  13  mm. 
in  length  and  n  mm.  in  breadth.  They  are  common  in  the 
whole  of  Central  America  (Garrapatas),  and  attack  mammals, 
amphibious  animals  and  man.1 

Hyalomma  cegyptium  (L.),  1758. 
Syn.  :    Acarus  cegyptius,  L.,  1758  ;  Ixodes  camelinus,  Fischer,  1823. 

A  species  frequently  found  in  Africa,  particularly  in  Egypt 
and  Algeria,  and  which  also  occurs  in  France  and  Italy,  as  well 
as  in  Asia.  Male  8  mm.  in  length,  4-5  mm.  in  breadth.  Female 
up  to  24  mm.  in  length  and  15  mm.  in  breadth.  It  infests  large 
and  small  animals  as  well  as  human  beings.2 

[This  is  one  of  the  largest  ticks,  nearly  reaching  the  size  of  the 
Bont  tick.  It  is  known  in  Africa  as  the  Bont  leg-tick  ;  all  farm 
stock  is  attacked,  but  sheep  and  goats  suffer  most.  Only  one 
generation  appears  to  occur  each  year.  The  male  is  almost  black 
with  a  pale  marginal  stripe ;  the  replete  female  brown  with 
irregular  light  blue  stripes.  It  is  abundant  in  parts  of  South 
Africa.— F.  V.  T.] 


1  Neumann,  G.  L.,  cf.  p.  205. 

2  Neumann,  G.  L.,  cf.  p.  285  ;    Ronsisvalle,   "  Sui  fenomeni  morb.  prodotti  nel  uomo 
da  un  Jxodide  'denominate  Hyol.  eeg."  (Boll.  Ace.  Gioenia  sc.  nat.,   1891,  xvii.). 


368  THE    ANIMAL    PARASITES    OF    MAN 

Hcemaphysalis  punctata,  Canestrini  and  Fanzago,  1877-8. 

[Syn.  :  Hcemaphysalis  sulcata,  Canastrini  and  Fanzago,  1877-78  ;  Rhico- 
cephalus  expositicius,  Koch,  1877  ;  Hcemaphysalis  peregrinus,  Cambridge,  1889  ; 
Herpetobia  sulcata }  Canestrini,  1890. 

This  species  does  not  appear  to  be  common.  It  occurs  on  sheep, 
goats,  horses  and  cattle.  I  have  seen  a  female  taken  from  man  in 
Britain.  The  female  when  fasting  is  3-44  mm.  long,  when  gorged 
12  mm.  long.  Colour,  reddish-brown,  leaden-grey  when  gorged ; 
dorsal  shield  deeply  indented  in  front  ;  rostrum,  shield  and  legs 
brownish ;  body  finely  punctate,  both  above  and  below  ;  sexual 
opening  opposite  the  coxae  of  the  second  pair  of  legs  in  both  sexes. 
Palpi  a  little  longer  than  the  labium  ;  first  segment  short  and 
narrow,  second  and  third  widened  on  the  dorsal  face.  Coxae  with  a 
short,  broad  blunt  spine  ;  tarsi  short,  terminated  with  a  spur  on 
the  first  pair.  The  male  is  3*10  mm.  long.  Body  rather  narrow, 
yellowish  to  reddish-brown  ;  dorsal  shield  nearly  covers  the  whole 
body  ;  numerous  punctures  over  the  whole  surface.  Eleven  indenta- 
tions on  the  posterior  margin  of  the  body ;  peritremes  lighter  in 
colour,  large  and  comma-shaped.  The  three  anterior  pairs  of  legs 
with  a  short  spine  on  the  haunches,  the  fourth  with  a  very  long  one 
directed  backwards.  The  nymph  varies  from  2*5 — 3*0  mm.,  is  oval, 
and  light  yellow  to  dark  red  in  colour.  Dorsal  shield  rounded  with 
few  punctations.  No  spur  on  tarsi,  and  sexual  orifice  nearly  obsolete, 
Larva  short  and  oval.  Length  1*20  mm. — F.  V.  T.] 

Dermacentor  reticulatus  (Fabricius),  1794. 

Syn.:    Acarus  reticulatus,  Fabr.,   1794;  Ixodes  reticulatus,  Latreille,   1806; 
Ix.  marmoratus,  Risso,  1826. 

This  tick  is  provided  with  eyes,  but  it  is  distinguished  from  Ixodes 
and  analogous  genera  by  the  lack  of  the  abdominal  plastron  in 
the  male,  which  measures  5 — 6  mm  in  length  by  3-5  mm.  in  breadth. 
The  female  may  attain  16  mm.  in  length  and  10  mm.  in  breadth. 
It  is  found  in  the  South  of  Europe,  in  Asia,  and  in  America  ;  it 
attacks  chiefly  oxen,  sheep  and  goats,  and  occasionally  man.1 
[This  tick  sometimes  causes  much  annoyance  to  human  beings. 
It  has  been  most  troublesome  at  Revelstoke.  Specimens  have 
recently  been  found  on  fowls  in  Kent. — F.  V.  T.] 

'Neumann,  G.,  "Rev.  de  la  fam.  des  Ixodides"  (Mem,  soc.  zooL,  France,  1897, 
*.,  P-  360). 


ARGAS    REFLEX  US  369 

Other  synonyms  are  as  follows  : — Cynorhcestes  pictus,  Hermann,  1804  ; 
Crotonus  variegatus,  Dumeril,  1829;  Ixodes  pictus,  Gervais,  1844;  Derma - 
centor  albicollis,  Koch,  1844-47  ;  Dermacentor  pardalinus,  Koch,  1844-47  > 
D.  ferrugineus,  Koch,  1844-47  ;  Ixodes  holsatus,  Kolenati,  1857;  Pseudixodes- 
holsatus,  Haller,  1882  ;  Hcsmaphsalis  marmorata,  Berlese,  1887. 

The  female  when  fasting  is  3-86  mm.  long  by  2  mm.  wide. 
The  body  is  depressed,  larger  behind  and  reddish-brown  in  colour. 
The  shield  is  very  large  and  extends  to  the  level  of  the  third  pair 
of  legs,  with  a  few  large  and  many  small  punctuations,  milky  white, 
variegated  with  reddish-brown.  Sexual  orifice  opposite  the  coxae 
of  the  second  pair  of  legs.  Coxae  of  the  front  legs  are  deeply 
bifid,  the  others  with  a  moderate  spine.  When  gorged  light 
brown,  and  may  reach  16  mm.  When  depositing  eggs  the  female 
is  mottled  with  dark  brown  above  and  below.  The  male  is  like 
the  female.  The  shield  is  reddish-brown,  variegated  with  a  milky- 
white  pattern.  Coxae  of  the  fourth  pair  of  legs  three  times  the 
size  of  the  third.  There  is  a  sharp  backwardly-pointing  spine  on 
the  second  palpal  segment,  also  seen  (but  smaller)  in  the  female. 
Length  4*20  mm. 

[According  to  Mr.  Wheler  this  is  a  very  variable  species  both 
in  size  and  colour.  It  occurs  in  England  on  sheep,  but  not  com- 
monly. It  has  probably  been  introduced  into  Britain.  Besides 
the  animals  mentioned  above  it  is  also  found  on  deer. — F.  V.  T.]. 

Rhipicephalus  sanguineus  (Latreille),   1804. 

Syn.  :  Ixodes  sanguineus,  Latr.,  1804  ',  Ixodes  rufus,  Koch,  1844  ;  Rhipi- 
cephalus limbatus,  Koch,  1844;  Rh.  siculus,  Koch,  1844;  Rh.  stigmaticus, 
Gerstacker,  1873. 

Spread  over  almost  the  entire  tropical  and  sub -tropical  regions, 
occurring  in  Europe  in  the  South  of  France  and  in  Italy  ;  it  infests 
dogs  and  more  rarely  sheep ;  oxen,  cats,  foxes  and  human  beings 
are  also  attacked.1 

Argas  reflexus  (Fabricius),  1794. 

Syn.  :    Acarus    reflexus,    Fabricius,    1794  ;    Acarus    marginatus,   Fabricius,  . 
1794;  Rhynchoprion  columbte,  Hermann,  1804. 

The  Argasinae  are  distinguished  from  the  Ixodinae  by  the  head,  which  in 
the  former  is  situated  on  the  inferior  aspect  of  the  cephalo thorax,  while 
in  the  Ixodinae  it  projects  freely  ;  also  by  the  very  short  proboscis,  the 

1  Neumann,  G.  L.,  c.  1897,  P-  385- 
24 


370  THE    ANIMAL    PARASITES    OF    MAN 

small  club-like  palpi,  the  lack  of  suckers  on  the  legs,  as  well  as  by  the 
scutellum,  which  covers  the  entire  back  and  is  bent  up  round  the  borders. 
Two  genera  are  distinguished:  Argas,  Latreille,  1796  (Rhynchoprion,  Hermann, 
1804),  and  Ornithodoros,  Koch,  1844.  The  species  live  on  mammals,  but  more 
especially  on  birds. 

The  European  Marginated  Tick,  Argus  reflexus  (length  of  male 
4  mm.,  breadth  3  mm.,  length  of  female  6 — 8  mm.,  breadth  4  mm.) 
is  of  a  yellowish  colour  and  has  yellowish- white  legs.  The 

ingested  blood  shows  red  or  brown  through 
the  intestine,  which  is  provided  with  blind 
sacs.  It  lives  in  dove-cots.  It  remains 
hidden  during  the  day  and  at  night  crawls 
on  to  the  sleeping  pigeons  to  suck  their 
blood.  It  has  been  observed  in  France, 
England,  Italy,  Germany,  and  Russia.  Per- 
sons sleeping  near  infected  dove-cots,  or  in 
apartments  formed  from  pigeon  lofts,  are 
FIG  2^8  —  Ar  as  re-  a^so  Stacked,  even  when  the  room  in  ques- 
ftexus  from  the  dorsal  sur-  tion  has  not  been  used  for  sheltering  pigeons 

ttSu^h^aj^^SS  for  years>  as  "marginated  ticks"  can  live  in 
(After  Pagenstecher.)  a  fasting  condition  for  a  very  long  time.  The 

bite  sometimes    gives    rise   to    serious  symp- 
toms, such  as  general  erythema  and  sudden  oedema.1 

[This  pest  more  often  feeds  on  the  blood  of  man  than  is 
imagined.  Blanchard  states  that  he  has  received  them  from 
men's  clothes  in  Strasbourg.  Boschulte,  of  Westphalia,  records 
these  parasites  in  a  bedroom  inhabited  by  children  and  connected 
with  a  pigeon  house.  The  children  were  bitten  during  sleep  on  the 
hands  and  feet.  The  result  of  the  bite  was  intense  itching 
along  the  nerves,  the  bite  only  being  marked  by  a  red  spot.  In 
a  girl  of  14  or  15,  vesicles  were  formed  similar  to  those  produced 
by  burns,  and  in  an  old  man  an  ulcer  formed.  Others  record 
painful  punctures  and  persistent  cedema  produced  by  this  pigeon 
pest.  It  was  once  abundant  in  Canterbury  Cathedra],  and  often 


1  Raspail,  V.,  "  Rech.  d'hist.  nat  sur  les  insectes  morbipares"  (Gaz.  des  hopitaux, 
i8'39,  i.,  p.  9);  Boschulte,  "  Argas  reflexus  als  Parasit  des  Menschen"  (Virchow's 
Arch.,  1860,  xviii.,  p.  554;  1879,  Ixxv.,  p.  562);  Gerstacker,  A.,  "Argas  reflexus, 
ein  neuer  Parasit  des  Mensch."  (ibid.,  1860,  xix.,  p.  457);  Alt.  K.,  "Die  Taubenzecke 
als  Parasit  des  Menschen  "  (Miinch.  med.  Wochenschr.,  1892,  No.  30  ;  and  Centralbl. 
fur  Bact.,  1893,  xiv.,  p.  468) ;  Neumann,  G.,  "  Rev.  de  la  Jam.  d.  Ixodides.  I."  (Mem. 
soc.  zool.,  France,  1896,  ix.,  p.  4)  ;  Gibert,  J.  M..  "  L'argas  reft,  et  son  paras,  chez  I'homme. 
These  de  Bordeaux,"  1896  (Centr.  f.  Bakt.,  Par.  und  Inf.,  xxiii.,  p.  515);  Brandes,  G., 
"  Arg.  reft,  als  gelegentl.  Paras,  d.  Mensch  "  (Centr.  f.  Bakt.,  Par.  und  Inf.,  1897,  xxii., 
p.  747). 


ARGAS    PERSICUS  371 

caused  much  annoyance,  I  am  told,  to  the  worshippers  ;  the  ticks 
falling  down  from  the  roof,  where  they  were  living,  derived  from  the 
numerous  pigeons  that  breed  in  the  towers.  This  acarus  has 
enormous  powers  of  vitality,  living  without  food  for  months  at 
a  time.— F.  V.  T.] 

Argas  persicus,  Fischer  de  Waldheim,  1824. 

Of  oval  form  and  brownish-red  colour.  The  male  measures  4 — 5 
mm.  in  length  by  3  mm.  in  breadth  ;  the  female  7—10  mm.  in  length 
by  5 — 6  mm.  in  breadth.  It  frequents  the  entire  north-west  and  north- 
east of  Persia  (the  Gerib-gez  or  Malleh  of  the  Persians,  the  Miana-bug 
of  travellers).  It  lives  concealed  in  houses  and  attacks  man  at 
night  to  suck  his  blood.  Its  bite  is  much  dreaded,  but  the 
serious  results  may  probably  be  attributed  to  unsuitable  treat- 
ment of  the  wound  or  its  invasion  by  bacteria.1 

[This  tick,  sometimes  called  the  Tampan  and  Wandlius  in 
South  Africa,  is  mainly  a  fowl  parasite. 
Fowls  and  ducks  frequently  die  under  its 
attack,  particularly  young  ones  ;  death 
being  due  to  loss  of  blood.  This  tick 
remains  attached  to  its  host  during  its 
larval  stage  for  about  five  days,  it  then 
leaves  and  moults  in  concealment.  In  its 
subsequent  stages  it  visits  its  host  by 
night  and  remains  for  about  an  hour  only, 
during  which  time  it  distends  itself  fully 
with  blood.  As  a  nymph  it  moults  twice, 
not  once  as  do  the  cattle  ticks.  This  tick  Megnin.) 
and  other  Argas  become  larger  with  each 

moult,  but  retain  their  same  general  appearance.  The  female, 
visits  the  host  every  now  and  then,  and  between  deposits  eggs  in 
sheltered  crevices.  About  50  to  120  are  deposited  at  once. 
Four  weeks  seem  a  necessary  period  to  intervene  between  visits 


1  Oken,  L.,  "  Ueb.  gift.  Milben  in  Persien  "  (I sis,  1818,  p.  1567^;  Fischer  de  Wald- 
heim G  "  Not.  sur  I' Acarus  de  Perse  "  (Mem.  soc.  natur.  Moscou.,  1823,  vi.,  No.  30), 
Ann!  sc.'nat.,  1824,  ii..  P-  77;  Heller,  C.,  "  Z.  Anat.  d.  Arg.  pers."  (Stzgsb.  d  K.  k. 
Acad.  d.  Wiss.  Wien  ;  math-nat.  Cl.,  1858,  xxx.,  p.  297);  Fntsch,  G.,  Ueb  d.  gift, 
Wirkg  d  Aro,  pers  "  (Stzgsb.  d.  Ges.  nat.  Frde.,  Berlin,  1875,  p.  61);  Laboulbene,  A., 
et  P  Megnin  "  M'cm.  sur  les  Argas  de  Perse  "  (Journ.  de  I'anat.,  1882,  xvm.,  p.  317)  ; 
Megnin,  P.,  "  Exp.  sur  V action  nocive  des  Argas  de  Perse  "  (C.  R.  soc.  biol,  Pans,  1882, 
p.  305)  ;  Tholozan,  J.  D.,  "  Des  phenom.  morb.  prod,  par  la  piqfire  .... 
de  Perse  "  (ibid.,  p.  15);  Neumann,  G.  L.,  1896,  p.  7. 


372  THE    ANIMAL    PARASITES    OF    MAN 

to    the    host    and    the    interval    may    be    extended    to    upwards  of 
a  year  according  to  Lounsbury.1 

This  so-called  Persian  tick,  the  Miana,  which  is  such  a  scourge 
to  travellers  in  Persia,  appears  to  infest  the  huts  of  natives  in 
Persia.  It  has  recently  been  sent  me  from  Quetta,  where  it  has 
invaded  houses  to  such  an  extent,  the  natives  cannot  live  in  them. 
The  virulence  of  its  bite  is  probably  due  to  the  tick  trans- 
mitting fever  germs  from  natives,  probably  inured,  to  strangers,  who 
would  be  susceptible. — F.  V.  T.] 


Argas  chinche,  Gervais,  1844. 

This  acarus,  a  native  of  the  temperate  parts  of  Columbia,  is 
very  troublesome  to  man.  It  is  probably  identical  with  Argas 
americanus,  Packard,  which  infests  domestic  fowls  and  turkeys, 
and  occasionally  also  cattle,2  and  is  differentiated  from  Argas 
reflexus  by  the  sculpturing  of  the  cuticle. 


Ornithodoms  savignyi  (Audouin),  1827. 

Syn.  :  Argas  savignyi,  Aud.,  1827  ;  Ornithodorus  morbillosus,   Gerstacker,  1873  , 
Argas  monbata,  Murray,  1877  ;  Argas  schinzi,  Berlese,  1889. 

Differentiated  from  Argas  by  its  more  rectangular  body,  the 
peculiar  sculpturing  of  the  cuticle,  and  by  other  characteristics 
into  which  we  need  not  enter.  Ornithodorus  savignyi  has  eyes  ;  it 
occasionally  attains  a  length  of  12  mm.,  is  very  widely  spread  in 
Africa,  and  also  occurs  in  Asia  ;  its  bite  not  only  produces  local 
symptoms,  but  affects  the  general  health  more  or  less,  a  fact  that 
was  already  reported  by  Livingstone.3 

[This  tick  is  also  known  as  the  Tampan,  and  infests  stock 
as  well  as  man.  It  has  a  leathery  skin,  broadly  oval  in  form 
and  dull  mud-coloured,  and  seldom  reaches  more  than  five-eighths 
of  an  inch  in  length.  It  occurs  abundantly  in  the  Transvaal,  in 
Rhodesia,  Bechuanaland,  Cape  Colony,  German  South-west  Africa, 


1  Report  of  Government  Entomologist  for  1899,  Cape  of  Good  Hope,  p.  33  (1900.) 

2  Gervais,  P.,  Hist.  nat.  d.  Insect  apteres,  1844,  iii.,  p.  462  ;  Packard,  A.  G.,  "  Arach- 
nida  "  (U.  States  geol.  surv.  of  the  territ.),  1872, .p.  740;  Neumann,  G.,   1896,  p.  9. 

3  Audouin,   Descr.   de  I'Egypte,   2nd    edit.,   xxii.,   Zool.,    1827,    Explic.   d.    planch., 
p.   426;  Gerstaecker,   A.,    "  Gliederth.   Ostafrika's  von   C.   v.   d.  Deckens  Reise,"   1873, 
p.  464;  Murray,  "  Econom.  Entomol.,"   1877,  *••  P-   182;   Neumann,  G.,  1896,  p.  26. 


ORNITHODORUS  373 

and  Portuguese  East  Africa.  It  occasioned  considerable  annoy- 
ance to  the  troops  during  the  South  African  war.  It  frequents 
for  preference  the  shade  of  vegetation,  but  is  found  in  exposed 
places,  and  also  invades  the  native  huts.  All  animals  seem  to 
be  attacked,  but  it  has  a  decided  preference  for  man.  This 
species  also  occurs  abundantly  in  Uganda  and  bites  natives  severely, 
causing  a  fever  from  which  they  may  die  in  a  short  time.  I  have 
recently  received  numbers  alive  from  the  Uganda  Protectorate.  This 
is  the  species  connected  with  the  recently  discovered  disease  in  man- 
Tick  Fever.— F.  V.  T.] 

Ornithodorus  turicata  (Duges),  1876. 

Without  eyes.  Indigenous  in  Central  .America  ;  attacks  human 
beings  and  pigs.  The  bite  is  painful  and  is  often  followed  by 
serious  consequences.1 

[So  virulent  is  this  species  that  pigs  put  in  an  infested  sty 
often  die  in  a  night.  This  "  turicatas  "  of  Mexico  often  reaches 
6  mm.  in  length. — F.  V.  T.] 


Ornithodorus  talaje  (Guerin-Meneville),  1849. 

Syn.  :   Argas  T  at  age,  Guer.-Men. 
Likewise  without  eyes  and  a  native  of  Central  America.2 

Ornithodorus  tholozani  (Laboulbene  and  Megnin),  1882. 
Syn.  :    Argas  tholozani,  Lab.  and  Meg.,  1882. 

Without  eyes.  Males  4—6  mm.  in  length  and  2—4  mm.  in 
breadth  ;  females  8— 10  mm.  in  length  and  4—5  mm.  in  breadth. 
It  especially  attacks  sheep.  Native  of  Persia.3 

[This  species  is  reputed  as  being  very  dangerous  ta  man.  It 
is  locally  known  as  the  kene,  or  sheep-bug.  In  its  fully  gorged 
state  it  is  deep  violet. — F.  V.  T.] 

1  Megnin,  P.,  "  Les  Argas  du  Mexique  "  (Journ.  de  I'anat.  et  de  la  phys..  1885,  xxi., 
p.  463;  Neumann,  G.,  1896,  p.  31;  Duges,  A.,  "  PiqAre  de  Turicata"  (C.  R.  soc, 
biol,  Paris,  1885,  ii.,  p.  216). 

-  Guerin-Meneville,  "  Descr.  de  I'Arg.  tal."  (Rev.  et  mag.  de  zool.,  1849,  p.  342  ; 
Megnin;  P.,  "  Les  arg.  de  Mex."  (I.e.,  p.  460)  ;  Neumann,  G.,  I.e.,  1896,  p.  34. 

3  Laboulbene,  A.,  and  P.  Megnin,  "  Mem.  sur  les  Argas  de  Perse  "  (Journ.  de  I'an. 
et  de  la  phys.,  1882,  xviii.,  p.  333);  Neumann,  G.,  I.e.,  1896,  p.  38. 


374  THE    ANIMAL   PARASITES   OF    MAN 

Ornithodorus  megnini  (Duges),  1883. 
Syn.  :   Argas  megnini,  Duges,  1883. 

Length  8'5  mm.,  breadth  5*5  mm.      Native  of  Mexico.1 

[Another  synonym  for  this  species  is  Rhynchoprion  spinosum, 
Marx.  Wheler  describes  the  nymph  as  follows  :  Length  3  mm.  to 
4  mm.  fasting,  to  9  mm.  when  replete.  Body  brown,  diamond  shaped, 
with  the  rostrum  exposed  before  repletion.  Rostrum  beneath  the 
body  and  the  latter  squarer  after  distension.  Palpi  filiform.  Legs  far 
apart  and  coxae  almost  entirely  concealed  beneath  the  skin.  Surface 
of  the  anterior  half  of  body  covered  with  small  brown  spines, 
replaced  by  whitish  hairs  posteriorly,  which  are  specially  numerous 
in  the  hinder  margin.  The  stigmata  are  placed  above  instead  of 
behind  the  fourth  pair  of-  legs.  These  differ  entirely  from  the  stigmal 
plates  and  peritremes  usually  present,  and  consist  of  cone-like  pro- 
jections pointing  backwards.  The  top  is  truncated  and  perforated 
by  an  orifice  ;  through  this  is  a  jointed  organ,  somewhat  resembling 
the  terminal  joints  of  the  palpi,  which  partially  fills  the  orifice  and 
is  furnished  with  three  hairs  at  the  end.  It  can  be  projected  and 
withdrawn  with  rapidity.  This  feature,  according  to  Neumann,  is 
absent  in  the  male.  The  female  is  stated  by  Neumann  to  differ 
greatly  from  the  nymph,  which  latter  attains  dimensions  at  least  as 
large  as  the  mature  adult. 

Two  specimens  in  the  nymphal  state  were  taken  from  the  ear  of 
an  American  visitor  to  Cambridge  by  Dr.  J.  Christian  Simpson. 
They  were  supposed  to  have  entered  the  ear  when  the  American 
was  camping  out  in  Arizona. 

This  species  attacks  the  horse,  ass  and  ox,  generally  around 
the  ears,  but  it  chiefly  attacks  man.  It  is  well  known  in  the 
United  States  as  infesting  the  ears  of  children  (New  York  Ent.  Soc. 
Journ.,  pp.  49-52,  1893).— F.  V.  T.] 

7.     Fam.  Tyroglyphidce. 

Very  small  mites  without  eyes  and  without   tracheae,-  with  smooth  skin. 

The  males  usually  have  a  suctorial  pore  on  either  side  of  the  anus,  which 

is  used  during  copulation,  or  suckers  may  be  found  in  both  sexes  near  the 

1  Duges,  A.,  La  Naturaleza,  Mexico,    1883,  v.,  p.    195;    Megnin,  P.,   "  Les  Argas 
de  Mexique  "  (Journ.  de  Van  et  de  la  phys.,  1885,  xxi.,  p.  460) ;  Neumann,  G.,  I.e.,  1896, 
p.  42  ;   Guerin,  in  Bull.  soc.  chir.,  1867,  viii.,  p.  444 ;   Simpson,  J.  Ch.,   "  Case  of  Para- 
site (Arg.  Megn.)  in  each  ear  "  (Lancet,  1901,  No.  17,  p.  1197). 

2  [Cheyletus  has  a  distinct  and  peculiar  tracheal  system. — F.  V.  T.] 


TYROGLYPHUS  375 

sexual  orifice.  The  mouth-parts  form  a  cone  with  chelate  chelicerae,  and 
three-jointed  pedipalpi  ;  the  legs  are  usually  short,  have  five  segments  with 
a  terminal  claw  and  suckers,  or  either  one  or  other  of  these  organs.  The 
numerous  species  and  genera  live  free  and  from  choice  in  slowly  decom- 
posing vegetable  and  animal  matter  (cheese,  cereals,  flour,  sugar,  pre- 
serves, dried  anatomical  preparations,  bacon,  dried  fruits  and  fungi),  also 
in  the  corners  of  dwellings,  &c.  ;  they  incidentally  get  into  or  on  to  man, 
or  are  found  in  chamber  utensils  and  in  spittoons  ;  actual  parasites  are 
rarely  found  amongst  them.1 

[The  chief  genera  are  Tyroglyphus,  Glyciphagus,  Rhizoglyphus  and  Chey- 
letus.  The  first  three  have  typical  characters  referred  to,  but  are  dis- 
tinguished from  each  other  by  the  two  former  having  the  hairs  on  the 
dorsum  smooth,  whilst  in  Glyciphagus  they  are  hairy,  plumose,  or  feathered. 
Rhizoglyphus  can  be  told  from  Tyroglyphus  by  having  claws  on  the  tarsi 
without  any  suckers  ;  Tyroglyphus  has  both  claws  and  suckers.  Cheyletus 
has  enormous  mandibles  and  a  peculiar  tracheal  system ;  two  ungues  and 
appendages  to  the  tarsi. — F.  V.  T.] 

Tyroglyphus  farince  (De  Geer). 

The  male  measures  0-33  mm.  in  length  by  0*16  mm.  in  breadth  ; 
the  female  o'6  mm.  in  length  by  0*3  in  breadth.  These  mites 
possess  five  pairs  of  suctorial  organs  of  a  light  colour  ;  the  legs  are 
reddish.  Moniez  observed  them  in  Lille  on  the  skin  of  labourers 
•who  had  been  unloading  Russian  corn.2  A  few  of  the  species 
generally  mentioned  under  the  designation  of  Tyroglyphus  siro  are 
probably  the  common  Flour-mite,  which  also  occurs  on  dry  cheese. 

Tyroglyphus  siro  (L.). 

Male  0-5  mm.  in  length  by  0*25  mm.  in  breadth  ;  'female  0-53 
mm.  in  length  by  0-28  mm.  in  breadth  ;  the  males  have  two 
suckers  on  the  tarsi  of  the  fourth  pair  of  legs.  Penis  straight. 
Colour  whitish  or  reddish. 


Tyroglyphus  longior,  Gervais,  1844. 

White  or  yellowish,  with  two  black  spots  on  the  abdomen. 
Male  0-55  rnm.  in  length,  0*28  mm.  in  breadth  ;  penis  bent. 
Female  o  61  mm.  in  length  and  0-28  mm.  in  breadth. 

Tyroglyphus  siro  and  T.  longior  live  on  dry  cheese,  in  flour,  on 

1  Moniez,  R.,  "  Sur  les  Tyrogl.  qui  livent  aux  defiens  d.  mat.  alim.  ou  d.  prod,  phartn." 
(Rev.  biol.  du  Nord  de  la  France,  1899,  vi.).- 

2  Moniez,  R.,  "  Parasit.  accid.  sur  Vhomme  du  Tyr.  far."  (C.  R.  Ac.  sc.,  1889,  Paris/ 
cviii.,  p.   1026). 


376 


THE    ANIMAL   PARASITES   OF   MAN 


dried  fruits,  &c.,  and  have  been  occasionally  observed  in  the 
stools,  urine,  or  pus  of  human  beings,  and  also  on  their  skin. 
The  so-called  vanillismus  is  to  be  attributed  to  these  species.1 

[Tyroglyphus  siro  and  T.  farina  are  the  same.  They  are 
described  under  other  names,  such  as  A  car  us  lactis,  Linn. ;  Acarus 
favorum,  Herm.,  &c. ;  Acarus  lactis  in  milk  ;  farina  in  flour,  and 
siro  in  cheese. 

It  is  to  this  species  that  a  case  of  dysentery  was  referred. 
Rolander,  who  studied  under  Linnaeus,  was  attacked  by  what  was 
called  dysentery.  The  complaint  soon  gave  way  to  treatment. 


FIG.    240. — Tyroglyphus   farince,    male 
(enlarged).     (After  Berlese.) 


FIG.    241.  —  Tyroglyphus   longior, 
Gerv.     ( After  Fum.  and  Robin.) 


but  eight  days  after  it  returned,  soon  disappeared,  but  again 
came  a  third  time.  All  the  time  Rolander  had  been  living  like  the 
other  inmates  of  the  house,  who  all  escaped.  Linnaeus,  aware  that 
Bartholemy  had  attributed  dysentery  to  insects  which  he  said  he 
had  seen,  advised  his  student  to  examine  his  stool.  The  result 
was  that  innumerable  mites  were  found  to  be  present.  Their 
presence  was  easily  accounted  for  by  the  fact  that  they  were  found 
in  numbers  in  a  cup  made  of  juniper  wood  from  which  the  student 
alone  drank  of  a  night,  and  they  were  found  to  be  the»same  species. 
What  this  species  is  we  do  not  know.  Linnaeus  called  it  Acarus 
dysenteric.  No  records  have  occurred  since.  It  cannot  be,  as 
Latreille  supposed,  the  cheese-mite,  for  they  have  been  eaten  by 
millions  since,  and  it  is  strange  no  such  case  has  occurred. — F.  V.  T.] 


1  Layet,  A.,  "  Etude  sur  le  vanillisme  "  (Rev.  d'hyg.  et  de  policesanit.,  1883,  v.,  p.  711)- 


GLYCIPHAGUS  377 

Glyciphagus  prunomm,  Her.,  and  Gl.  domesticiis  (De  Geer). 

The  Glyciphagi  are  differentiated  from  the  Tyroglyphi  in 
that  the  chitinous  hairs  on  the  body  are  toothed  or  feathered, 
and  that  they  lack  a  furrow  dividing  the  cephalothorax  from  the 
abdomen.  They  live  under  similar  conditions  to  the  Tyroglyphi 
and  are  occasionally  found  on  man  or  in  faeces.1 

[Sugar  merchants  and  grocers  are  frequently  troubled  by 
swarms  of  these  acari,  which  leave  their-  stores  when  being 
handled,  especially  shopmen,  who  handle  sugar  kept  in  small 
stores  for  some  time.  These  are  the  acari  that  cause  that  irritating 
temporary  affection  known  as  "  grocer's  itch." 

Glyciphagus  cursor,  Gervais. 

Under  this  name  Signor  Moriggia2  figures  a  horny  excrescence 
of  gre.at  length  growing  from  a  woman's  hand,  and  containing  in 
its  cavities  quantities  of  Acarus  domesticus.  It  seems  that  this 
species  is  really  G.  cursor. 

Glyciphagus  buski,  Murray.3 

This  is  a  mite  found  by  Busk  and  named  after  him  by  Murray. 
It  was  taken  from  beneath  the  cuticle  of  the  sole  of  the  foot  of 
a  negro  in  the  Seamen's  Hospital  Ship  on  the  Thames  in  1841, 
in  large  sores  of  a  peculiar  character  confined  to  the  soles  of  the 
feet.  It  appeared  that  the  disease  was  caused  by  its  burrowing 
beneath  the  thick  cuticle.  The  disease  was  attributed  to  the 
wearing  of  a  pair  of  shoes  which  had  been  lent  to  another  negro 
whose  feet  had  been  similarly  affected  for  nearly  a  year.  The 
negro  to  whom  the  shoes  were  lent  came  from  Sierra  Leone.  Mr. 
Busk  stated  that  some  water  brought  by  Dr.  Stranger  from  the 
river  Since,  on  the  coast  of  Africa,  contained  one  nearly  perfect 
specimen,  and  fragments  of  others  very  similar  if  not  identical  with 
this  Acarus.  Mr.  Busk  adds  that  he  had  been  informed  by  Staff- 
Assistant  Surgeon  P.  D.  Murray  that  at  Sierra  Leone  there  is  a 
native  pustular  disease  called  craw-craw — a  species  of  itch  breaking 
into  open  sores. 

From  Busk's  original  figure  I  see  no  reason  to  doubt  that  this 
is  a  Glyciphagus. — F.  V.  T.] 

1  Perrier,  E.,  "  Cas  de  paras,  passager  du  Glyciph.  dom."    (C.  R.  Ac.  sc.,  Paris,  1896, 
cxxii.,  p.  859). 

2  Atti.  A  cad.  Set.,  Torino  I.,  p.  449,  1867. 

8  Cooper  and  Burk's  Microscopic  Journal,  1842,  and  "  Economic  Entomology," 
Murray,  p.  280. 


378 


THE   ANIMAL   PARASITES   OF   MAN 


Rhizoglyphus  parasiticus,  Dalgetty,  1901. 


The  Rhizoglyphii  are  to  be  recognised  by  their  short  legs,  which  are  beset 
with  spines,  and  by  the  tarsi,  which  terminate  in  a  claw.  They  live  on  plants, 
roots  and  bulbs,  especially  the  bulbs  of  lilies. 

This  species  has  been  observed  on  the  feet  of  Indian  coolies 
working  in  the  tea  plantations ;  they  produce  a  skin  disease 


a,  b, 

FIG.  242. — Rhizoglyphus  parasiticus,  enlarged  ;  a,  male  ;   b,  female.     After  Dalgetty. 

which  always  commences  with  blebs  between  the  toes,  and  which 
almost  always  extends  to  the  malleoli,  but  not  beyond.  The 
acari  have  an  elliptical  body,  which  is  grey,  but  varies  from 
greenish-yellow  to  greenish-brown  when  the  stomach  is  full.  Eyes 
are  absent.  The  legs  are  composed  of  five  segments  and  terminate 
with  a  claw.  The  males  measure  0*18  mm.  in  length  by  0*08  mm. 
in  breadth,  and  possess  genital  and  anal  pores  :  the  females  measure 
0*2  mm.  in  length  by  0*09  mm.  in  breadth.1 

Histiogaster  spermaticus,  Trouessart,  1900. 

The  genus  Histiogaster,  .which  also  approaches  the  Tyroglyphinee ,  is 
characterised  by  the  circumstance  that  the  males  possess  suctorial  pores 
used  in  copulation,  as  well  as  leaf-shaped  appendages  at  the  posterior  end 
of  the  body.  They  feed  on  vegetables,  especially  on  small  fungi. 

1  Dalgetty,  A.  B.,  "Water-Itch;  or,  Sore  Feet  of  Coolies"  (Journ.  Trop.  Med., 
1901,  iv.,  p.  73). 


SARCOPTID^  379 

This  species  has  been  described  by  Trouessart,  who  found 
numerous  specimens,  some  adult,  others  in  the  developmental  stage 
(larvae,  nymphs),  and  ova,  in  the  fluid  removed  by  puncture  from 
a  cyst  of  the  right  testis.  The  males  measure  0*25  mm.,  the 
females  0-32  mm.,  and  the  larvae  cvi  mm.  in  length.  The  author 
is  of  opinion  that  the  animal — perhaps  a  fertilised  female — was 
introduced  by  a  catheter,  and,  as  a  matter  of  fact,  it  was  after- 
wards found  that  the  patient  had  had  once  the  catheter  passed 
in  India  while  suffering  from  pernicious  fever.1 


[Cheyletus  mericourti,  Lab.  (Acaropsis  mericourti,  Moq.  Tand.). 

This  mite  has  been  described  from  three  specimens  found  in 
pus  which  flowed  from  an  abscess  in  the  ear  of  a  naval  officer, 
produced  by  inflammation  of  the  auditory  passage.  Where  the 
mites  came  from  we  do  not  know,  as  they  were  found  near  the 
Bank  of  Newfoundland.— F.  V.  T.j 


8.    Fam.  Sarcoptidce  (Itch  Mites). 

Small  mites  without  eyes  and  tracheae,  and  with  delicate,  transversely- 
striated  cuticle.  The  mouth-parts  form  a  cone,  over  which  the  shield-shaped 
upper  lip  protrudes  ;  the  chelicerae  are  scissor-shaped  ;  the  pedipalpi 
(or  maxillary  palpi)  have  three  joints  ;  the  legs  are  short  and  compact, 
and  composed  of  five  segments  ;  the  terminal  joints  have  pedunculated 
suckers  (ambulacra)  or  a  long  bristle.  The  larvae  are  six-legged.  They 
live  on  or  under  the  skin  of  birds  and  mammals,  on  which  they  produce 
the  skin  disease  known  as  scabies,  or  itch. 

[The  SarcoptidcB  attack  the  epidermis  of  animals  and  man,  living  as 
permanent  parasites.  The  punctures  they  produce  are  followed  by  the 
formation  of  more  or  less  thick  crusts  or  scabs,  beneath  which  the  mites 
live  and  breed.  Most  are  oviparous,  some  ovo viviparous.  The  eggs  are 
minute,  ovoid,  with  a  thin  semi-transparent  shell.  They  incubate  in  a  few 
days,  varying  from  two  to  ten  or  eleven,  as  a  rule.  Generally  sarcoptic 
diseases  lie  dormant  in  winter  and  revive  in  spring  and  summer  in  man  ; 
but  in  animals  with  long  wool,  such  as  sheep,  they  are  most  active  during 
winter,  although  revival  of  active  reproduction  takes  place  in  spring. 

Speaking  generally  for  the  Sarcoptidae,  there  are  three  distinct  stages 
in  the  development  of  the  male,  four  in  the  female,  as  follows  :— 

(1)  The  larva.      In  this  stage  only  three  pairs  of  legs  occur. 

(2)  The  nymph,  in  which  a  fourth  pair  of   legs  appear,  and  which  thus 


1  Trouessart,  E.,  "  Faux  parasit.  d'une  esp.  de  Sarcopt.  detnticole  dans  un  kyste 
du  testicule  chez  I'homme  "  (C.  R.  soc.  biol.,  Paris,  1900,  Hi.,  p.  742)  ;  "  Deuxieme  note 
suv  I' Hist,  spermat.  et  sa  pv'es.  dans  un  kyste  du  testic.  chez  I'homwe  ('ibid.,  p.  893). 


380  THE    ANIMAL   PARASITES   OF   MAN 

approach    the   adult  ;    but   so   far   no   sexual   organs   occur.     Nymphs   are   of 
two  sizes — the  smaller  being  future  males,  the  larger  females. 

(3)  The    next    stage   in    the    female    is    the    age    of   puberty  ;    the    female 
now  being  provided   with   a   vulvo-anal   slit  ;    this   so-called   pubescent  female 
is    fertilised    by    the    male.      The    male    then    dies.      But    the    female    again 
casts  her  skin  and  enters  another  stage,  the 

(4)  Ovigerous  female — the  egg-laying  female — which  has  differently  modi- 
fied legs. 

The  rate  at  which  these  acari  breed  is  very  great.  Gerlach  has  found 
that,  roughly,  in  each  Sarcopt  gallery  a  female  produces  fifteen  individuals — 
ten  females  and  five  males — and  that  the  progeny  reproduce  again  in  fifteen 
days.  The  table  given  below  thus  shows  that  one  pair  may  produce  the 
enormous  number  of  1,500,000  descendants  in  three  months  : — 
First  generation  after  15  days  :..-.  .  .-'.  10  females  ..  5  males. 

Second        ,,  ,,      30      ,,  •.;.,-     .  v;.--  100       ,,        ",'»-.'  50       ,, 

Third  „  „      45      ,,  .^V:';   ;••:  1,000   -.,  -,,,  ./;       . .  •. ,         500       „/ 

Fourth        „  ,,      60      ,,  .',      - •'- '. .-'-.       10,000        ,, : ••'       ..          5,ooo       „ 

Fifth  „  ..75      ..  ~-V,   N      ."./       100,000     .'»,''    '  ,".        50,000 

Sixth  ,,  ,,      90      ,,  v^r/;   ^Y^V   1,000,000     ;;^;.;  •'.  ...      500,000      :'^.- 

—  1,300,000  individuals. 

These  Acarinae  are  divided  into   three  distinct  genera  : — 

(1)  Sarcoptes,   Latreille. 

(2)  Psoroptes,   Gerv.  ;  Dermatodectes,   Gerlach  ;  Dermatocoptes,  Fiirstenberg. 

(3)  Symbiotes,  Gerlach  ;  Chorioptes,  Gerv.  ;  Dermatophagus,  Fiirst.  ;    Sarco- 
dermatodectes ,   Del. 

The   following   are   the   main   characters  of   these   three  genera  : — 

Sarcoptes — round  or  slightly  oval ;  the  two  posterior  pairs  of  legs  being 
nearly  or  quite  concealed  beneath  the  body  ;  the  tarsi  end  in  simple  long 
pedicles,  with  ambulatory  suckers. 

Psoroptes — oval  ;  the  legs  are  all  visible  outside  the  margin  of  the 
body  ;  the  ambulatory  suckers  are  carried  on  long  triangulated  stalks  ; 
the  male  has  copulatory  suckers  and  abdominal  prolongations. 

Symbiotes — oval  ;  legs  long,  thick,  all  visible  ;  ambulatory  suckers  very 
wide,  carried  at  the  end  of  simple,  short  pedicles. 

Sarcoptes  make  channels  or  furrows  beneath  the  epidermis,  and  in  these 
the  female  lays  her  eggs.  This  form  of  acariasis  is  thus  difficult  to  cure. 
It  is  the  cause  of  human  itch  (vide  Sarcoptes  scdbiei). 

Psoroptes  do  not  make  sub-epidermic  galleries  ;  they  live  and  breed  in 
colonies  beneath  crusts  or  scabs  formed  by  the  changes  they  produce  in 
their  host's  skin.  Sheep  scab  is  a  common  type  of  disease  produced  by 
Psoroptes.  This  genus  is  of  little  importance  as  a  parasite  to  man. 

Symbiotes  live  as  Psoroptes  ;  they  also  do  not  affect  man. — F.  V.  T.J 

Sarcoptes  scabiei  (L.),  1748. 

Syn.  :  Acarus  scabiei,  "L.,  1748;  A.  psoricus,  Pallas,  1760;  A.  siro,  L., 
1761;  Sarc.  exulcerans,  Nitsch,  1818  ;  5.  hominis,  Raspail,  1834;  S.  galei, 
Owen,  1853;  5.  communis,  Delaf.  et  Bourg.,  1862. 

The   body   is     oval    or    nearly   circular   and   whitish    in   colour. 


SARCOPTES   SCABIEI 


covered  by  transverse  rows  of  folds  partly  interrupted  on  the 
back.  There  are  transverse  rows  of  small  bristles  on  the  dorsal 
surface,  and  groups  of  trichomae  on  the  front,  sides  and  back. 
There  are  chitinous  hairs  at  the  base  of  the  legs  ;  the  two  first 
pairs  (of  legs)  are  provided  with  pedunculated  ambulacra  in  both 
sexes,  the  two  posterior  pairs  terminate  each  with  a  long  bristle 
in  the  female  ;  in  the  male  the  third  pair  of  legs  terminate  in  a 
bristle,  the  fourth  pair  with  a  pedunculated  ambulacrum.  The 
anus  is  situated  at  the  posterior  border  of  the  dorsal  surface. 

Formerly  numerous  kinds 
were  differentiated,  according 
to  the  form  of  the  acarus,  the 
number,  position  and  size  of 
the  prickles  and  spines,  even 
according  to  the  hosts,  &c. 
All  these  characteristics,  how- 
ever, fluctuate  so  consider- 
ably that  absolute  differ- 
entiation is  impossible  ;  the 
conjectural  species  might 
almost  be  regarded  in  the 
same  light  as  Megnin  did, 
as  varieties.  It  is  also 
hardly  possible  to  distin- 
guish the  mite  of  human 
scabies  {Sarcoptes  hominis} 
from  that  of  a  ,  number  of 
domestic  animals  (S.  squami- 
ferus'}.  The  simplest  plan, 
therefore,  is  to  accept  one 
single  species  -  -  Sarcoptes 
scabiei — which  may  give  rise 
to  different  races  or  varieties 
by  living  in  the  skin  of  man 
and  a  few  mammals,  but  can 
pass  from  one  host  to  the  other. 

The  Sarcoptes  scabiei  of  man  (Sarc.  scabiei,  var.  hominis) 
(length  of  male  0-2 — 0-3  mm.  and  breadth  0-145 — 0*190  mm.  ; 
length  of  female  033 — 0*45  mm.  and  breadth  0*25— 035  mm.)  lives  in 
the  tunnels  that  it  excavates  in  the  epidermis,  and  attacks  by  prefer- 
ence places  with  thin  skin,  such  as  between  the  fingers,  in  the  bend 
of  the  elbows  and  knees,  in  the  inguinal  region,  on  the  penis,  on 
the  mammae,  but  may  also  affect  other  parts.  The  tunnels,  from  a 
few  millimetres  to  a  centimetre  and  more  long,  do  not  run  straight, 
but  are  somewhat  tortuous  ;  the  female  is  found  at  the  terminal 
end,  The  tunnels  contain  the  excrements  and  oval  eggs  (0*14  mm. 


FIG.    243.  — Sarcoptes    scabiei,    female,     dorsal 
aspect.     200  i.     (After  Furstenberg.) 


382 


THE    ANIMAL    PARASITES   OF  MAN 


in  length)  of  the  parasite  ;  the  males  are  rarely  met  with  as  they 
die  off  after  copulation,  the  females  die  after  depositing  their 
eggs.  The  six-legged  larvae  hatch  out  after  four  to  eight  days, 
and  after  about  a  fortnight,  during  which  time  they  change  their 
skins  three  times  and  undergo  metamorphosis,  they  begin  to 
burrow  themselves.  Transmission  from  person  to  person  rarely  is 
effected  through  linen,  but  by  direct  contact  (as  in  coitus) ;  trans- 
mission can  be  artificially  effected  on  horses,  dogs,  and  monkeys, 
but  not  on  cats. 

The  smaller  Sarcoptes  scabiei  crustosce,  Fiirstenberg,  is  the  cause 

of  the  scabby  itch  that  occurs 
chiefly  in  Norway ;  it  is  not 
yet  certain  whether  this  is  a 
distinct  species  of  itch-mite. 
The  following  forms  may  be 
transmitted  from  DOMESTIC 

ANIMALS    to    MAN  :— 

(1)  Sarcoptes    scabiei,    var.    equi. 
Male,  0*2 — 0*23  mm.  long  ;    0*16 — 
0*17  mm.  broad.      Female,   0-40 — 
0*42    mm.    long,    0*28 — 0^32    mm. 
broad.      The    horse   is    the    normal 
host. 

(2)  Sarcoptes    scabiei,    var.    ovis. 
Male,   0*22    mm.    long;    0*16   mm. 
broad.     Females,  0-32  —  0-44   mm. 
long -0*24 — 0*36  mm.  broad.     This 
mite    lives    on    sheep,    and    passes 
over   to  goats  and  human  beings  ; 
it    may    also    be    artificially   trans- 
ferred  to  horses,  oxen,   and  dogs. 

(3)  Sarcoptes   scabiei,  var.  caprce. 

FIG.   244.-Sarcoptes  scabiei,  male,  ventral.    Male>    °'24    mm.    long,    0*188    mm. 
aspect.    200  i;     (After  Fiirstenberg.)  broad.      Female,    0*345    mm.    long, 

0x342     mm.     broad.       On      goats, 

passing  from  them  to  horse,  ox,  sheep,  pig  and  man.     In  the  latter,  in  con- 
tradistinction  to   the   varieties    i    and    2,    it   produces   a   severe  affection. 

(4)  Sarcoptes  scabiei,  var.  cameli.     Frequently  observed  in  man,  chiefly  in 
Africa.      A  few  cases  have  been  observed  in  Europe  ;    the  affection  induced 
by  it  is  severe. 

(5)  Sarcoptes  scabiei,    var.  auchenice.     Male,    0*245    mm.    long,    0*182   mm. 
broad.     Female,  0*34  mm.  long,  0*264  mm.  broad.     It  lives  on   the    Llama, 
and  may  be  transmitted  to  man. 

(6)  Sarcoptes  .  scabiei,  var.    suis.     Male,    0*25 — 0*35    mm.     long,    0*19 — 0*3 


[This  mite  produces  the  so-called  "  Black  muzzle  "  of  sheep. — F.  V.  T. 


SARCOPTES     MINOR 


3»3 


mm.  broad.  Female,  0-4 — 0-5  mm.  long,  0*3 — 0-39  mm.  broad.  In  the 
domestic  pig  and  wild  boar  ;  occasionally  also  in  man.  The  settlement, 
however,  is  usually  of  short  duration. 

(7)  Sarcoptes  scabiei,  var.  canis.  Male,  O'i9 — 0^23  mm.  long,  0*14 — 
o'i/  mm.  broad.  Female,  0^29 — 0-38  mm.  long,  0-23— o'28  mm.  broad. 
In  the  house-dog,  and  also,  not  unusually,  in  human  beings. 

(8  and  9)  Sarcoptes  scabiei,  var.  vulpis,  and  Sarcoptes  scabiei,  var.  leonis, 
of  the  fox  and  lion  ;  have  likewise  been  observed  on  man. 


Sarcoptes  minor,  Fiirstenberg,  1861. 

Anus  situated  on  the  back,  legs  short,  pedunculated  ambulacra 
broad  ;  living  on  cats  (S.  minor,  var.  cati)  and  rabbits  (S.  minor, 
var.  cuniculi).  In  cats  this  mite  usually  lives  in  the  cervical 


FIG.  245.—  Sarcoptes  minor,  var.  cati.—  On  the  left,  female  (lying  on  its  abdomen).; 
on  the  right,  male  (lying  on  its  back).  (After  Railliet.) 

+      * 

region,  and  thence  spreads  to  the  ears  and  head  ;  it  usually  causes 
the  death  of  the  infected  animals  ;  it  is  easily  transferable  from 
cat  to  cat,  is  difficult  to  transmit  to  rabbits,  but  once  settled  on 
them  can  easily  infect  other  rabbits.  On  the  other  hand,  the 
transmission  of  the  itch-mite  of  the  rabbit  to  the  cat  does  not 
succeed.  In  man  Sarcoptes  minor  induces  an  eruption  that  dis- 
appears after  about  a  fortnight. 

The  itch  mites  of  domestic  animals,  which  belong  to  the  genera 
Psoroptes  (  =  Dermatodectes  =  Dermato copies}  and  Chorioptes  (Symbiotes  =  Derma- 
tophagus},  as  a  rule  do  not  infest  and  live  on  man,  even  when  artificially 
transmitted.  It  is,  however,  possible  for  this  to  occur.  Thus  Moniez 
(Traitt  de  paras.,  1896,  p.  559)  mentions  that  a  species  of  Chorioptes— 
probably  Ch.  bovis— had  been  found  on  man,  as  had  also  Demodex  fotticu- 
lorum.  This  author  also  includes  Dermatophagoides  scheremetewskyi,  Bogdanoff 
(Bull.  soc.  imp.  d.  natural.,  Moscow,  1864,  xxxvii.,  p.  341),  which  has 


THE   ANIMAL    PARASITES    OF    MAN 


repeatedly    been  found    on    man  in    Moscow  and    Leipzig  (Ziirn.  Ber.   d.   med. 
Ges.,   Leipzig,    1877,   p.    38),   as   Chorioptes   bovis.1 

Nephrophages  sanguinarius,  Miyake  and  Scriba,  1893. 

Males  measure  0*117  mm.  in  length  and  0*079  m  breadth  ;  females 
up  to  0-360  mm.  in  length  by  o- 120  mm.  in  breadth.  The  head 
is  provided  with  two  very  large  scissor-like  jaws  and  two  large 
round  eyes.  The  legs  are  composed  of  five  segments  and  are  all 
of  equal  length  ;  the  three  anterior  pairs  of  legs  have  peduncu- 
lated  ambulacra,  the  posterior  ones  terminate  in  a  claw.  The 


FIG.  246. — Nephrophages  sanguinarius,  en- 
larged. Male,  ventral  surface.  (After  Miyake 
and  Scriba.) 


FIG.  247. —  Nephrophages  san- 
guinarius, female,  dorsal  aspect,  en- 
larged. (After  Miyake  and  Scriba.) 


1  The  most  important  literature  respecting  the  Sarcoptidce  :  Hertwig,  C.,  "  Ueber 
Krcitz  und  Rdudemilben"  (Arch.  f.  Naturgesch.,  1835,  i.,  p.  398);  Gurlt  and  Hertwig., 
Vergl.  Unters.  ub.  d.  Haut  d.  Menschen  u.  ub.  d.  Kratz  milben.,  Berlin,  1844  '•  Fiirsten- 
berg,  M.  H.  F.,  Die  Krdtzmilben  des  Menschen  u.  d.  Thieve.,  Lpzg.,  1861  ;  Bourguignoii, 
H.,  "  Rech.  s.  la  contag.  de  la  gale  des  animaux  a  I'homme  "  (Mem.  soc.  biol.,  Paris,  1851, 
iii.,  p.  109,  Ann.  d.  sc.  nat.,  1855,  iii.,  p.  114);  Megnin,  P.,  "Mem.  sur  I'acclim.  des 
acariens  psoriques  des  animaux  sur  d'autr'es  esp.  anim.  et  sur  I'homme  "  (La  France 
medicate,  1876,  xxiii,  p.  166)  ;  Megnin,  P.,  "  Sur  certains  details  anat.  que  presentent 
Vespe.ce  Save.  scab,  et  ses  nombreuses  var."  (C.  R.  Ac.  sc.,  Paris,  1875,  Ixxxi.,  p.  1058)  ; 
Bergh,  R.,  "Ueber  Borkenkrdtze  "  (Virchow's  Arch.,  1860,  xix.,  p.  i,  and  Vier.tel- 
jahrssch.  /.  Dermat.  u.  Syphilis,  1874,  vi.,  p.  491);  Megnin,  P.,  "  Les  acariens  para- 
sites, Paris  "(Encycl.  scientif.  d.  ai  de-memoir  e,s) ;  Weydemann,  "  Sarc.  vulpis  b.  Mensch." 
(C.  f.  B.  u.  P.,  1897,  xxii.,  p.  442);  Canestrini,  G.,  and  P.  Kramer,  "  Demodicidce 
u.  Sarcoptidce"  (Das  Thierreich.,  vol.  vii.,  Berlin,  1899);  Alexander,  A.,  "  Uebertrag. 
d.  Thierkrdtze  auf  Mensch."  (Arch.  f.  Dermatol.  u.  Syph.,  1900,  Iii.,  p.  185). 


DEMODICID^  385 

cuticle  on  the  back  is  thickened  in  three  places,  shield-like  ;  the 
abdominal  surface  without  scutellum  is  longitudinally  striped,  and 
is  beset  with  chitinous  hairs.  Colour  greenish  to  brownish-yellow. 
Eggs  o'O46-o'O40  mm. 


The  authors  discovered  these  mites,  but  always  dead,  in  the  urine  of  a 
Japanese  suffering  from  fibrinuria  (complicated  with  chyluria  and  haematuria). 
They  surmised  that  they  were  endoparasites,  probably  situated  in  the  kidney  ; 
but  this  view  is  not  convincing,  though  they  also  report  that  for  a  week, 
day  after  day,  the  mites  were  found  in  the  patient's  urine,  as  well  as  in 
urine  drawn  off  by  means  of  a  catheter,  and  in  the  water  used  to  wash 
out  the  bladder  fone>  or  two  specimens  and  an  egg).  The  statement  that 
these  mites  have  large  eyes  makes  the  discovery  suspicious,  to  say  the 
least.  The  significance  of  the  discovery  is  not  supported  by  the  further 
statement  that  Disse  is  supposed  to  have  found  an  encapsuled  mite  closely 
related  to  the  Tyroglyphides  on  the  wall  of  the  vena  cava.1 

In  the  case  of  Marpmann,  who  found  a  dead  Acarid  in  the  urine  of 
a  man  suffering  from  chronic  nephritis,  and  in  whom  later  examinations 
proved  negative,  the  author  himself  was  of  opinion  that  the  mite  had  reached 
the  urine  from  outside.2  , 

We  are  certainly  acquainted  with  mites  living  endoparasitically,  namely, 
the  Cysticolae  Analgesinae,  of  which  Laminosioptes  gallindrum  live  in  the 
intra-muscular  and  subcutaneous  connective  tissue  of  fowls,  and  Cytoleichus 
sarcoptoi'des  in  their  air-sacs.  Another  kind  of  mite  (Halarachne  halichceri] 
is  occasionally  found  in  the  nasal  mucous  membrane  of  the  seal  (Hali- 
chcerus  grypus\  and,  quite  recently,  Pneumonyssus  simicola,  which  is  more 
nearly  related  to  Halarachne,  has  been  found  in  the  lung  of  Cynocephalus  sp. 
It  is,  therefore,  not  beyond  the  bounds  of  probability  that  endo- 
parasitic  mites  are  found  in  man  ;  but  no  discovery  has  hitherto  been 
made  that  is  sufficiently  convincing  to  banish  all  doubts.3 

9.     Fam.  Demodicidce  (Mites  of  the  hair  follicles). 

Small  acarina,  elongated  in  worm-like  fashion,  with  annulated  abdomen,  and 
without  eyes  or  tracheae.  The  mouth  parts  consist  of  a  suctorial  proboscis 
and  three  jointed  palpi  ;  the  legs  are  short,  and  have  three  segments  with 


1  Miyake,  H.,  and  J.  Scriba,  "  Vorl.  Mitth.  iib.  ein.  neuen  Paras,  d.  Mensch."  (Berl. 
klin.    Wchsch.,    1893,   No.    16,   p.    374),    "  Nephroph.    sang.,    ein  neuer  menschl.  Par   i. 
Urogenitalapp  "  (Mitth.  a.  d.  med.  Facult.  d.  K.  jap.   Univ.,  iii.,  p.   i). 

2  Marpmann,  "  Ueb.  d.  Votk.  v.  Milben  i.  Harn."  (Centr.  f.  Bakt.,  Paras.,  u.  Infekt., 
1898,  xxv.,  p.  304). 

3  Me^nin    P     "  Mim.  sur  les  Ac.  par.  du  tissu  cellul.  et  des  hours,  atrienn.  chez  les 
oiseaux  "  (Jouni  de  Van.  et  de  la  phys.,   1879);  Allman,  G.,  ;(  Descr.  of  a  New  Gen. 
of  Trach     Arach."  (Ann.  and  Mag.  of  Nat.  Hist.,  1847,  xx.,  p.  47.) ;   Kramer,  P.,      Ueb. 
Halarach   halich."   (Zeitsch.  f.  d.  ges.  Naturw.,   Halle,   1885,  Iviii.,  p.  46);    Grijns,  G., 
and  J.  De  Haan,  "  Acar.  als  cndop."  (Geneesk.  Tijdsch.  v.  Nederl.  Indie.,  1901,  part  41, 
i     p    176)'  Banks,  N.,    "A  New  Genus  of   Endop.,  Acar."  (ibid.,   p.  334);    Haan,  J. 
de,  and  G.' Grijns,  "  Eine  neue  endop.  Acaridc  "  (C.  i.  B.,  P.  uAI.  [i],  1901,  xxx.,  p.  7); 

25 


386 


THE   ANIMAL   PARASITES   OF   MAN 


small  terminal  ungues.  The  anus  is  situated  on  the  anterior  border  of 
the  abdomen  ;  oviparous  ;  the  larvae  have  six  stumpy  legs.  These  mites 
live  in  the  hair  follicles  of  mammals. 

Demodex  folliculorum  (Simon),  1842. 

Syn :  Acarus  folliculorum,  Sim,  1843;  Dem.  folliculorum,  Owen,  1843; 
Macrogaster  platypus,  Miescher,  1843;  Simonea  folliculorum,  P.  Gervais,  1844; 
Steatozoon  foil.,  Wilson,  1847. 

As  in  Sar copies  scabiei,  numerous  varieties  of  this  species  are 
known  ;  the  form  parasitic  on  man  lives  in  the 
hair  follicles,  the  meibomian  and  sebaceous  glands, 
and  hardly  e.ver  causes  inconvenience  ;  the  male 
measures  0*3  mm.  in  length,  and  the  female  about 
0*4  mm.  in  length.  The  eggs  0*06 — 0*08  in  length, 
0*04 — 0*05  in  breadth,  and  are  thin-shelled.  The 
creatures  are  always  attached  with  the  head-end 
downwards  in  the  parts  mentioned  ;  they  are  most 
frequent  in  the  sebaceous  glands  of  the  face, 
by  the  nose,  lips  and  forehead,  but  they  may 
be  present  on  the  abdomen  and  on  other  parts  of 
the  body.  They  may  occasionally  obstruct  the 
excretory  gland  ducts,  thus  causing  inflammation 
of  the  gland  (comedones)  ;  their  agglomeration  in 
the  meibomian  glands  sets  up  inflammation  of 
the  margins  of  the  eyelids.  There  are  generally 
only  a  few  specimens  in  a  gland.  According  to 
some  statements  Demodex  occurs  in  50  per  cent, 
of  mankind  and  even  in  children  ;  they  survive 
the  death  of  their  hosts  by  several  days. 

The  variety  living  in  the  dog  (Dem.  folliculorum,  var.  cam's)  is  smaller  than 
the  variety  living  in  man,  and  produces  a  skin  disease  resembling  scabies 
in  these  animals.  According  to  Ziirn  they  may  also  live  on  man  ; 
nevertheless,  no  other  investigator  has  recorded  a  similar  observation, 
and  attempts  at  artificial  infection  have  proved  negative.1 

Simon,  G.,  "  Sur  les  acares  vivant  dans  les  follicules  pileux  de  I'homme  "  (Arch, 
de  medec.  comp.,  1843,  i.,  p.  45);  Leydig,  F.,  "  Ueb.  Haarsackmilben  u.  Kriitzmilben  " 
(Arch.  f.  Naturg.,  1859,  xxv.,  p.  338)";  Landois,  L.,  "  Ueb.  d.  Haarbalgparas.  d.  Men- 
schen"  (Greifswald.  med.  Beitr.,  1863,  L,  p.  17);  Stieda,  L.,  "  Ueb.  d.  York.  d.  Haar- 
balgparas. an  den  Augenlidern"  (Centralbl.  f.  prakt.  Augenhlkde.,  1890,  July,  p.  193)  ; 
Thudichum,  J.  S.  W.,  "  On  the  Dem.  foil,  as  the  Par.  Caus.  of  the  Mange  of  Dog  and 
its  Transfer  upon  Man  ",(Med.  Press  and  Circ.,  1894,  p.  103);  Majochi,  D.,  "Int.  al 
Dem.  foil,  nelle  ghiand.  meib.,"  Bologna,  1897  (£•  /.  B.,  P.  u.  I.,  xxv.,  p.  784);  Ivers, 
K.,  "  Demod.  s.  Ac.  foil.  u.  seine  Bez.  z.  Lidrandentzdg."  (D.  med.  Wochschr.,  1899, 
p.  220);  Raehlmann,  E.,  "  Ueb.  Blepharitis  acarica  "  (Kl.  Monatsb.  f.  Augenhlkde., 
1899,  xxxvii.,  p.  33,  ref.  in  C.  /.  B.,  P.  u.  I.,  xxvi.,  p.  40). 

1  [This  mite   causes  what  we  know  in  England  as  Red  Mange  in  dogs. — F.  V.  T.] 


FIG.  248. — Demo- 
dex folliculorum  of 
the  dog.  (After 
Megnin.) 


LINGUATULA   RHINARIA  387 

Order  Linguatulidce  (Tongue  Worms). 

Arachnoidea  greatly  altered  in  consequence  of  their  parasitic  manner  of 
life  ;  for  a  long  time  they  were  regarded  as  Helminthes.  The  body  is  elongated, 
vermiform,  flattened  or  cylindrical,  and  more  or  less  distinctly  annulated. 
The  head,  thorax,  and  abdomen  are  not  denned  from  each  other  (fig.  249). 
The  elliptical  mouth,  surrounded  by  a  chitinous  ring,  is  situated  at  the 
anterior  end,  on  the  ventral  surface,  and  the  intestine  leading  straight 
through  the  body  opens  at  the  posterior  end.  Two  hooks,  retractile  into 
grooves,  are  set  at  both  sides  of  the  mouth  (fig.  250)  ;  these  are  usually 
considered  to  be  the  terminal  joints  of  two  pairs  of  legs,  but  it  appears 
to  be  more  correct  to  regard  them  as  the  remains  of  the  antennae  and" 
palpi  (Stiles).  According  to  this  opinion,  the  legs  in  the  adult  state  would 
be  completely  degenerated. 

The  nervous  system  is  reduced  to  an  ossophageal  ring.  No  organs  of 
sense  are  recognisable  except  the  papillae  at  the  anterior  end.  There  are 
neither  organs  of  circulation  nor  respiration.1 

The  sexes  are  distinct.  In  the  small  male  the  sexual  orifice  is  situated 
ventrally  in  the  anterior  part  of  the  body  ;  in  the  female  it  is  placed 
near  the  anus.  The  Linguatulidce  lay  eggs,  and  from  each  egg,  after 
being  conveyed  into  an  intermediate  host,  a  four-legged  larva,  with  rudi- 
mentary mouth  parts,  hatches  out.  It  goes  through  a  series  of  meta- 
morphoses, and  passes  through  a  second  larval  condition,  which,  however, 
possesses  the  essential  characteristics  of  the  fully  developed  form.  Sooner 
or  later  it  migrates  during  this  stage,  and  reaches  its  final  host,  mammal  or 
reptile,  in  the  nostrils  or  lungs  of  which  the  adult  Linguatulidce  live. 

Linguatula  rhinaria  (Pilger),  1802. 

Syn.  :    Tcenia  rhinaria,    Pilger,    1802  ;    Polystoma    tcenioides,    Rud.,    1810  ; 
Linguatula  tcenioides,  Lam.,   1816. — Pentastoma  tcenioides,  Rud.,   1819.  • 

The  male  is  white  in  colour,  18—20  mm.  in  length,  anterior 
portion  3 — 4  mm.  in  breadth,  posterior  part  0-5  mm.  in  breadth. 
The  female  is  of  a  yellowish  colour,  8,  10,  or  13  cm.  long,  anterior 
part  8—io  mm.  and  posterior  part  2  mm.  wide.  The  brownish 
eggs  can  be  seen  in  the  median  line.  The  body  is  elongated, 
rather  flat,  and  exhibits  about  ninety  rings  or  segments  and 
crenellated  borders.  The  hooks  round  the  mouth  are  strongly 
curved  and  are  articulated  to  a  basilar  support.  Eggs  oval,  0-09  in 
length,  0-07  in  breadth. 

Linguatula  rhinaria,  in  the  adult  condition,  lives  in  the  nasal 
cavity  and  frontal  sinus  of  the  dog,  wolf,  fox,  horse,  goat,  and 
occasionally  of  man  ;  it  causes  severe  catarrh,  epistaxis  and 
suppuration. 

1  What  are  designated  as  stigmata  in  the  Linguatulides  are  the  orifices  of  seba- 
ceous glands. 


388 


THE   ANIMAL   PARASITES    OF    MAN 


DEVELOPMENT. — The  ova  which  are  found  in  masses  in  the 
nasal  mucus  already  possess  an  embryo  ;  they  are  expelled  with 
the  nasal  secretion,  and  are  swallowed  by  herbivorous  mammals 
with  their  food,  mostly  by  hares  and  rabbits,  but  also  by  sheep, 
goats,  oxen,  horses,  antelopes,  fallow  deer,  pigs,  cats,  and  occa- 
sionally also  by  human  beings.  The  young  larvae  hatch  out  in  the 
stomach  ;  they  possess  a  thickened  anterior  body  with  rudimen- 
tary mouth  parts  and  two  pairs  of  limbs  ;  the 
body  gradually  tapers  to  a  short  tail. 

The  larvae  of  the  Linguatulidce  bore  through  the 
intestinal  wall  and  reach  the  liver,  more  rarely  the 
mesenteric  glands,  &c.  ;  they 
here  become  encysted  and  enter 
a  sort  of  pupal  stage  in  which 
they  lose  their  limbs  ;  after 
several  moultings  and  gradual 
growth  the  second  larval  stage, 
having  the  appearance  of  the  adult 
Linguatula,  sets  in.  About  five 
to  six  months  after  infection 
the  creatures  have  become  4 — 6 
mm.  long,  possess  eighty  to 
ninety  rings,  which  have  a  series 
of  fine  points  on  their,  posterior 
border  ;  the  mouth  and  intestine 
are  formed,  the  sexual  organs 
mature  and  the  two  pairs  of 
hooks  are  near  the  mouth. 
This  larval  stage  (fig.  250)  has 
been  known  for  a  lon^  time, 
,  but  it  was  regarded  as  an  inde- 

FIG.  249,—Lzngua-      FIG.  250.— Larva  of  •  r          •        i 

tula     rhinaria,     fe-      Linguatula  rhinaria       pendent    SpCClCS    OI    animal,     and 

male,  natural  size.      \*^ffi™t£^*£_      therefore  had    a    separate   name 
kart).     Enlarged.         (Linguatula    serrata,    Fr.,    Penta- 
stoma  denticulatum,    Rud.,    &c.). 

The  further  course  of  these  Lingvafula-larvst  is  only  peculiar 
in  so  far  as  they  make  efforts  to  leave  their  hosts,  and  this 
can  only  take  place  by  active  movements  ;  they  abandon  the  cysts 
that  harbour  them,  and  according  to  their  situation  in  the  abdominal 
or  pleural  cavity,  they  reach  either  the  bronchi  or  the  intestine, 
and  thence  finally  reach  the  open  ;  here  they  are  sniffed  up  by 
dogs,  &c.,  and  settle  themselves  in  the  nasal  cavities.  But  these 


LINGUATULA    RHINARIA  389 

migrations  are  not  essential  for  further  development  ;  it  is  probable 
that  some  of  the  larvae  reach  the  nasal  cavity  direct  by  way  of 
the  trachea,  thus  infecting  herbivorous  animals  direct.  In  other 
cases  the  infection  of  dogs,  wolves,  foxes,  beasts  of  prey,  takes 
place  through  their  devouring  mammals  or  parts  of  them  (liver, 
lungs)  which  harbour  the  larval  form ;  it  may  be  conjectured 
that  at  all  events  most  of  the  larvae  are  thus  first  imported  into 
the  stomach  of  their  hosts,  and  thence,  having  bored  through 
the  intestinal  wall  and  diaphragm,  invade  the  lungs,  and  by  way 
of  the  bronchi,  trachea,  &c.,  finally  find  their  way  to  the  nasal 
cavities  ;  possibly  also  some  larvae  find  their  way  to  the  nasal 
cavities  from  the  mouth  while  the  food  is  being  masticated. 
After  becoming  stationary  another  moulting  takes  place,  the 
cuticle  with  the  pointed  edges  is  discarded,  and  the  parasites 
become  adult  after  six  or  seven  weeks. 

Linguatula  rhinaria  has  been  observed  in  man  in  the  adult  as 
well  as  in  the  larval  condition  (Pentastoma  denticulatum}.  Zenker  first 
called  attention  to  the  occurrence  of  the  larva  in  man,  having  found  it 
nine  times  in  the  liver  in  168  autopsies.  Heschl  found  it  twice  in  Vienna 
in  20  autopsies,  Virchow  found  it  in  Wiirzburg  and  Berlin,  Wagner  in 
Leipzig  (10  percent.),  and  Frerichs  in  Breslau  five  times  in  47  autopsies. 
The  parasite  is  much  less  frequent  in  Switzerland.  According  to  Klebs, 
one  case  occurs  in  900  autopsies,  and  according  to  Zaeslin  two  cases 
occurred  in  Basle  to  1,914  autopsies.  In  the  seamen's  hospital  in  Kron- 
stadt  Pentastoma  denticulatum  has  been  found  six  times  in  659  autopsies. 
It  was  almost  always  the  liver  that  contained  one  or  a  few  specimens. 
The  parasite  was  very  rarely  found  in  the  kidney  or  spleen,  or  encysted 
in  the  intestinal  wall.  The  adult  Linguatula  rhinaria  is  far  more  rarely 
observed  in  man. 

A  case  reported  by  Landon  that  related  to  a  blacksmith  of  Elbing  is 
particularly  interesting.  This  man  accompanied  the  campaign  of  1870  ; 
he  soon,  however,  fell  ill  with  pains  in  the  liver,  accompanied  by  icterus 
and  intestinal  disorders.  Soon  after  the  war,  and  after  the  symptoms 
were  reduced  to  icterus  and  weakness,  bleeding  of  the  nose  set  in  and 
continued  with  slight  intermissions  for  seven  years  ;  an  unpleasant  sensation 
of  pressure  in  the  left  nasal  cavity  set  in  with  inflammatory  swelling  of 
the  mucous  membrane.  At  last,  in  the  summer  of  1878,  when  the  pres- 
sure in  the  nose  had  considerably  increased,  a  Linguatula  was  expelled 
from  the  nose  with  a  violent  attack  of  sneezing,  and  lived  for  three  days 
longer  in  water.  The  bleeding  of  the  nose  then  ceased,  and  the  patient 
soon  recovered.  There  can  be  no  doubt  that  the  first  illness  was  con- 
nected with  the  invasion  in  the  liver  of  numerous  larvae  of  Pentastoma-, 
and  disappeared  after  their  encystment  ;  one  or  a  few  of  these  must 
subsequently  have  found  their  way  to  the  nose  and  settled  there.1 

1  Schubart,  T.  D.,  "  Entw.  v.  Pent,  tanioides  "  (Z.  /.  w.  Z.,  1852,  iv.,  p.  116).— 
Zenker,  F.  A.,  "  Ueber  einen  neuen  thier.  Paras,  d.  Mensch."  (Zeitschr.  /.  rat.  Med. 


39°  THE   ANIMAL    PARASITES    OF   MAN 

Porocephalus  constrictus  (v.  Siebold),   1852. 

Syn.  :  Nematoideum  hominis,  Diesing,  1851  ;  Pentastomum  constrictum, 
v.  Sieb.,  1852  ;  Porocephalus  constrictus,  Stiles,  1893. 

Porocephalus  is  distinguished  from  Linguatula  by  its  cylindrical 
body  and  by  certain  internal  structures.  Porocephalus  constrictus 
is  as  yet  only  known  in  its  larval  stage.  It  is  milk-white  in 
colour  with  golden-yellow  hooklets.  Number  of  rings,  twenty-three. 
Length  13  mm.,  breadth  2*2  mm.  There  are  no  prickles  on  the 
posterior  border  of  the  annulations  of  the  body. 

This  species  was  first  discovered  by  Pruner  encysted  in  the  livers  of  two 
negroes  in  Cairo.  Bilharz  reported  two  further  cases  in  which  the  para- 
sites were  encysted  in  the  liver  and  in  the  mucosa  of  the  intestine  ;  a  few  other 
observations  have  been  made  by  Fenger,  Aitken,  Giard  and  Chalmas.  Aitken's 
report  deals  with  soldiers  of  the  British  Colonies  in  Africa.  The  parasites 
were  discovered  in  the  liver  as  well  as  in  the  lung,  and  appear  to  have 
been  the  cause  of  death  in  one  case  (pneumonia,  peritonitis). 

Pruner  has  found  the  same  parasite  also  in  the  liver  of  the 
giraffe.1 

B.  Myriapoda. 
See  Text   of   Braun,   p.   314   (footnote   2). 

C.  Insecta  (Hexapoda). 

Three  separate  divisions  can  always  be  distinguished  in  the  body  of 
insects,  namely,  the  head,  thorax  and  abdomen.  The  HEAD  is  a  roundish 
unsegmented  capsule  and  possesses  four  pairs  of  appendages.  The  first  pair 


1854,  v.,  p.  212);  "  Id.  Pent.  dent,  in  der  Niere  "  (Arch.  /.  phy.  Hlkde.,  1856,  xv., 
p.  581 ) ;  "  Id.  Pent.  i.  d.  MHz  "  (Arch.  f.  Hlkde.,  1862,  iii.,  p.  478).— Virchow,  R.,  "  Helmin- 
thol.  Notizen  I."  (Arch.  f.  p.  An.,  1857,  xi-»  P-  81). — Leuckart,  R.,  "  Bau  u.  Entwick- 
elungsgesch.  d.  Pentast.,  Lpzg.,  1860. — Colin,  In  Bull.  soc.  mtd.  vet.,  1861,  v.,  p.  125  ; 
1863,  vii.,  p.  22  ;  1864,  viii.,  p.  108. — Welch,  F.  H.,  "  The  presence  of  an  encysted 
Echinorhynchus  in  Man  "  (The  Lancet,  1872,  ii.,  p.  703). — Landon,  "  Ein  casuistischer 
Beitr.  z.  JEtiol.  d.  Nasenblut."  (Berl.  kl.  Wchschr.,  1878,  xv.,  p.  730). — Lohrmann,  E., 
"  Unters.  ub  d.  anat.  Bau  d.  Pentast."  (Arch.  /.  Naturg.,  1889,  lv.,  i.,  p.  303). — Stiles, 
C.  W.,  "  Bau  u.  Entiv.  v.  Pent,  proboscideum  u.  P.  subcylindricum  "  (Z.  /.  w.  Z.,  1891, 
lii.,  p.  85.)— Ratz,  St.  "  v.  V.  d.  activ.  Wanderung  d.  Pent,  denticulatum  "  (C.  f.  B.  u.  P.. 
1892,  xii.,  p.  329). — Shipley,  A.  E.,'"  An  Attempt  to  Revise  the  Family  Ling uatuli dee," 
(Arch',  de  parasit.,  1898,  i.,  p.  52).— Kulagin,  N.,  "  Z.  Naturgesch.  d.  Pent,  denticul." 
{C.  /.  B.,  P.  u.  I.,  1898,  xxiv.,  pp.  489  and  525). 

'Pruner,  Krankheiten  des  Orients,  Erlange,  1847,  P-  249- — Bilharz,  "Ein  Beitrag 
zuv  Helminthogr.  humana"  (Z.  f.  w.  Z.,  1852,  iv.,  p.  65). — Bilharz,  "  Uebers.  ub.  d.  i. 
Moypten  beob.  Eingeweidew/trmer  "  (Z.  d>  Ges.  d.  Mvzte,  Wien.,  1858,  i.,  p.  447). — 
Aitken,  W.,  "  On  the  Occurrence  of  Pent,  const,  in  the  Human  Body  as  a  cause  of 
painful  Disease  and  Death  "  (Science  and  pract.  of  Medicine,  4th  edit..,  London,  1865). — 
Giard,  A.,  "  Pent,  constr.,  par  du  foie  des  negres  "  (C.  R.  soc.  biol.,  Paris,  1896.  iii., 
p.  460  ;  Ref.,  C.  f.  B.,  P.  u.  I.,  xxiii...  p.  1098). — Chalmers,  A.,  "  Case  of  Pent,  constr." 
iThe' Lancet,  1899,  June  24)  '•  Ref->  C-  /•  B->  P-  u-  f->  xxvi.,  p.  518.— Neumann,  G., 
41  Sur  les  Poroceph.  du  chien  et  de  quelq.  mammif."  (Arch,  de  Paras.,  1899,  ii.,  p.  356). 


INSECTA  391 

are  the  various  shaped  feelers  (antennae)  which  are  placed  on  the  superior 
surface  of  the  head  next  to  the  eyes  ;  then  more  ventrally  placed  a  pair 
of  upper  jaws  (mandibles)  without  palpi  and  without  articulations  ;  they 
are  powerful  masticatory  organs.1  The  first  pair  of  lower  jaws  (maxillae) 
are  jointed  and  bear  a  palpus  (palpus  maxillaris)  ;  the  second  pair  of 
maxillae  are  soldered  together  and  form  the  lower  lip  (labium),  and  likewise 
carry  a  palpus  labialis  on  each  side.  The  upper  lip  (labrum")  as  well  as 
a  few  other  pieces,  which,  however,  are  only  appendages,  belong  to  the 
mouth,  which  is  really  formed  of  a  number  of  closely-united  pieces. 
The  mouth  parts  undergo  manifold  metamorphoses  according  to  the  func- 
tions required  of  them.  Coleoptera,  Neuroptera  and  Orthoptera  have 
biting  or  masticatory  mouth  parts  which  conform  with  the  scheme  described 
above.  In  the  licking  mouth  parts  of  the  hymenoptera  the  maxillae  and 
under  Up  are  considerably  elongated,  while  the  mandibles  retain  their  form 
and  are  used  for  triturating  the  food  :  in  the  Lepidoptera  nearly  all  the 
mouth  parts  are  shortened  except  the  maxillae,  which  form  a  long  and  some- 
times spirally  rolled  suctorial  proboscis  ;  the  Diptera  and  Rhynchota  have 
piercing  and  sucking  mouth  parts.  The  mandibles  and  maxillae  are  meta- 
morphosed into  a  needle-like  organ,  while  the  suctorial  apparatus  is  formed 
by  the  labrum  (compare  p.  97). 

The  thorax  consists  of  three  segments  which  are  frequently  completely 
united  ;  ventrally  it  carries  three  pairs  of  legs,  which  consist  of  a  definite 
number  of  articulated  pieces  joined  one  to  the  other.  Their  form  also 
changes  according  to  their  function,  so  that  legs  for  running,  walking, 
digging,  swimming,  jumping,  and  preying  are  seen.  A  pair  of  wings  are 
respectively  joined  to  the  last  and  last  but  one  thoracic  rings,  and  these 
may  be  traced  back,  not  to  metamorphosed  appendages,  but  to  tracheal 
branchia.  They  are  composed  of  chitinous  membranes  supported  by  branched 
structures  (veins  or  ribs).  Their  size  and  formation  vary  ;  they  are  seldom  of 
equal  size  and  form  (Neuroptera)  ;  often  the  posterior  wings  are  larger  than 
the  anterior  wings,  the  former  then'  only  serving  as  protective  coverings  for 
the  latter  (Coleoptera),  or  the  anterior  wings  are  larger  (Lepidoptera),  or  the 
posterior  wings  are  shortened,  or  are  entirely  absent  (diptera) ;  and  finally 
there  are  insects  in  which  both  pairs  of  wings  are  lacking.2 

The  abdomen  retains  its  segmentation,  but,  with  the  exception  of  a 
few  groups  related  to  the  primitive  forms  of  insects,  has  no  appendages  in 
the  imago  condition  ;  the  abdomen  usually  consists  of  ten  segments,  on 
the  last  of  which  the  anus  is  situated. 

We  need  only  observe  the  following  points  in  considering  the  anatomy 
of  insects. 

The  EPIDERMIS  consists  of  the  chitinous  cuticle,  which  is  separate  from 
the  cellular  layer  beneath  (hypodermis)  ;  the  various  appendages  are  sup- 
ported by  the  chitinous  layer. 


1  [The  mandibles  are  only  powerful  masticatory  organs  in  biting-mouthed  insects 
(Mandibulata);  in  the  sucking  or  piercing-mouthed  insects  they  may  be  absent  or 
in  the  form  of  needle-like  styles  (Haustellata). — F.  V^  T.] 

-  [As  in  the  order  Aptera,  which  includes  the  Thysanura  and  Collembola,  and  also 
exceptions  in  other  orders,  as  the  fleas  amongst  Diptera ;  the  Mutillas  and  ants 
amongst  Hymenoptera. — F.  V.  T.] 


39.2  THE   ANIMAL    PARASITES    OF    MAN 

The  INTESTINAL  CANAL  usually  consists  of  the  anterior,  median  and 
terminal  intestine,  and  as  a  rule  passes  straight  through  the  body  ;  a 
number  of  salivary  glands  discharge  into  the  anterior  part,  and,  in  some 
cases,  yield  a  stiffening  secretion  which  serves  for  spinning  webs  ;  numerous 
or  scanty  hepatic  tubes  are  appended  to  the  median  intestine,  while  on 
the  border  between  the  median  and  terminal  intestine  open  four  to  six 
long  tubes  (vasa  malpighiana),  which  act  as  urinary  organs.  Finally  the 
end  portion  of  the  intestine  carries  various  glands  (anal  and  rectal  glands,  &c.) 

The  CENTRAL  NERVOUS  SYSTEM  agrees  in  structure  with  that  of  the 
annelids,  but  is  more  highly  developed.  The  pharyngeal  ring  surrounds 
the  front  part  of  the  intestine  ;  the  sensory  nerves  originate  from  its 
SUPERIOR  PHARYNGEAL  GANGLIA  and  are  the  seat  of  the  higher  psychical 
functions  ;  the  INFERIOR  PHARYNGEAL  GANGLIA  govern  the  mouth  parts, 
and  in  addition  appear  to  regulate  the  movements  (cerebellum  of  the 
vertebrates). 

The  chain  of  GANGLIA  lying  on  the  ventral  side  of  the  abdomen  con- 
sists primitively  of  pairs  of  ganglia  corresponding  to  the  twelve  segments, 
which  are  connected  by  longitudinal  and  transverse  commissures.  But 
many  changes  in  the  ganglia  may  be  seen  in  insects  caused  by  partial  or 
entire  amalgamation  of  single  ganglia,  so  that  in  a  few  cases  only  one 
abdominal  ganglion  is  present.  In  conclusion,  a  definite  INTESTINAL  NER- 
VOUS SYSTEM  is  always  present. 

Of  the  organs  of  sense  the  FACETTED  EYES,  situated  at  the  sides  of  the 
head,  deserve  special  mention,  as  do  also  the  ORGANS  OF  TOUCH  and  SMELL, 
situated  on  the  antennae,  and  the  ORGANS  OF  HEARING  and  taste,  or  finer 
sensations,  situated  at  the  mouth  and  in  the  buccal  cavity. 

The  sounds  emitted  by  insects  are  as  a  rule  produced  by  the  friction 
or  beating  of  certain  chitinous  parts,  but  sounds  are  also  produced  in 
breathing  (flies). 

The  ORGANS  OF  RESPIRATION,  the  so-called  tracheae,  are  highly  developed  ; 
there  are  openings  (stigmata)  at  the  sides  of  the  body  which  draw  in  air 
by  means  of  the  active  participation  of  the  muscles  of  the  body.  The 
number  of  stigmata  varies  between  two  and  ten  pairs  ;  the  tracheae  them- 
selves branch  off  from  the  trunks  in  the  most  varied  manner,  and  carry 
air  to  the  internal  organs. 

The  colourless  BLOOD  circulates  between  the  tissues  and  organs,  and  is 
kept  circulating  by  the  contraction  of  a  chambered  dorsal  vessel  provided 
with  ostia,  and  which  terminates  in  a  short  aorta  opening  at  the  anterior 
end. 

Insects  are  SEXUALLY  DISTINCT  ;  their  sexual  glands  are  in  pairs  and 
have  a  tubular  structure,  but  the  testicular  tubules  are  united  together 
by  a  capsule  into  an  oval  testicle ;  exceptionally,  also,  the  excretory  canals  are 
double,  as  also  the  sexual  orifices ;  usually  the  paired  canals  unite  into  a  single 
oviduct  or  spermatic  duct  which  terminates  at  the  posterior  end  of  the  body 
after  receiving  the  products  of  various  glands. 

As  to  the  HISTORY  OF  THE  DEVELOPMENT  of  insects,  all  that  is  necessary  to 
mention  here  is  that  the  young  hatched  from  eggs  only  exceptionally  (as  in 
apterygota)  resemble  the  ackilt  parent  (insecta  ametabola)  ;  as  a  rule  they 
differ  from  them  not  only  in  the  shape  of  the  body,  but  also  more  or  less 
by  their  manner  of  life,  and  only  attain  the  form  of  the  parent  through 


INSECTA  393 

• 

METAMORPHOSIS.  This  is  a  gradual  process  (insecta  hemimetabola)  in  the 
Rhynchota  and  Orthoptera,  or  a  sudden  one  with  a  stage  of  inanition 
(insecta  metabola)  in  the  other  orders.  This  stage  of  rest  or  inanition, 
the  PUPA,  concludes  the  larval  life  (caterpillar,  maggot,  &c.)  ;  during  the 
pupal  stage  no  nourishment  at  all  is  taken,  but  the  internal  organs  undergo 
changes  ;  in  some  forms  the  rest  is  not  absolute,  as  voluntary  local  move- 
ments may  take  place  (pupae  of  gnats). 

The  insects  are  divided  into  numerous  orders  according  to  the  form  of 
the  mouth  parts,  the  structure  of  the  wings,  as  well  as  the  manner  of  the 
development  ;  with  the  exception  of  the  lowest  group  (Apterygota\  which 
is  most  nearly  related  to  the  ancestors  of  the  insects,  and  which  has 
no  wings  and  undergoes  no  metamorphosis,  all  the  remaining  orders,  which 
are  termed  Pterygota,  have  wings  on  the  thorax,  though  there  are,  of 
course,  a  few  species  and  families  of  this  order  which  have  secondarily  lost 
their  wings. 

The  Pterygota  include  : — 

(1)  Orthoptera. — Biting    mouth    parts,    anterior   wings    leathery,    posterior 

wings  thin,  folded  longitudinally  ;  metamorphosis  incomplete 
(Grasshoppers,  Crickets,  Cockroaches). 

(2)  Pseudoneuroptera. — Biting    mouth    parts,    wings    of    equal    size,    thin, 

not  folded  up  (Dragon-flies,   Hair  and  Feather  Lice,  Termites). 

(3)  Rhynchota   or   Hemiptera. — Mouth   parts   formed   for   puncturing   and 

sucking  ;  wings  alike,  or  the  anterior  wings  may  be  thickened, 
parchment-like  (Plant-lice,  Cicadae,  Bugs  and  True  Lice). 

(4)  Neuroptera. — Biting  mouth  parts  ;  wings  alike,   thin  ;  metamorphosis 

complete  (Ant-Lions,   Lace- Wing-Flies,   &c.). 

(5)  Trichoptera. — Licking     mouth    parts  ;     anterior    wings    narrow,    pos- 

terior wings  longitudinally  folded,  both  ornamented  with  little 
hairs  :  the  larvae  are  worm-like  in  form,  live  in  water,  and 
breathe  through  tracheal  gills  (May-flies,  &c.). 

(6)  Lepidoptera. — Suctorial     mouth     parts  ;     wings     covered     with     scales 

(Butterflies). 

(7)  Coleoptera. — Biting    mouth    parts  ;    anterior   wings    thickened  ;     they 

differ  in  colour,  appearance  and  function  from  the  thin,  folded 
posterior  wings  (Beetles). 

(8)  Hymenoptera. — Mouth    parts    for   licking    or  biting  :    the   wings   alike, 

membranous  (Ichneumon  flies,   Ants,  Wasps,  Bees,  Humble  Bees). 

(9)  Diptera. — Mouth  parts   formed   lor    puncturing,    sucking    or    licking  ; 

posterior   wings   degenerated   (Gnats,    Flies,    Gadflies,    Fleas.) 
(10)  Strepsiptera . — Anterior   wings   shortened  :    the    femak;    without    wings 

and   living   parasitically   (Fan-wings). 

The   parasites   of   man   occur   amongst   the   Rhynchota,    Coleop- 
tera,   and    amongst    the  Diptera. 

[The  most  usual  and  recent  classification  of  the  Hexapoda  is  the 
following  : — • 

(1)  Aptera. — Wingless  insects  ;   scarcely  any   metamorphosis. 

(2)  Neuroptera. — Four    membranous    wings,    frequently   with    much    net- 

work ;  the  front  pair  not  much,  if  at  all,  harder  than  the  under 
pair;  the  latter  with  but  little  or  no  fan-like  action  in  closing; 
mandibulate  ;  metamorphosis  variable,  but  rarely  complete. 


394  THE    ANIMAL   PARASITES    OF   MAN 

(3)  Orthoptera. — Four  wings ;  front  pair  coriaceous  or  leather-like,  usually 

smaller  than  the  other  pair,  which  are  of  more  delicate  texture 
and  contract  in  repose  like  a  fan  ;  mandibulate ;  metamorphosis 
complete. 

(4)  Thysanoptera. — Four  very  narrow  fringed  wings  ;  mouth  imperfectly 

suctorial  ;  metamorphosis  slight. 

(5)  Hemiptera. — Four    wings ;    the    front    pair    either    all    transparent    or 

with  the  basal  half  leathery  ;  mouth  suctorial  ;  metamorphosis 
slight. 

(6)  Diptera. — Two     membranous     wings     only  ;     mouth     suctorial,     very 

varied  ;   metamorphosis   complete. 

(7)  Lepidoptera. — Four    large    wings    covered    with    scales  ;    mouth    suc- 

torial ;   metamorphosis  great. 

(8)  Hymenoptera. — Four  membranous  wings  ;  front  pair  larger  than  hind, 

which  do  not  fold  up  in  repose  ;  mandibulate  mouth,  sometimes 
with  a  tubular  proboscis  ;  metamorphosis  complete. 

(9)  Coleoptera. — Four    wings,    the    front    pair    hard    and    horny    (elytra), 

meeting  in  a  line  over  the  back  and  covering  the  delicate  hind 
pair ;  mouth  mandibulate  ;  metamorphosis  complete. 

There  are  two  other  well  known  arrangements,  namely,  Packards 1  and 
Brauers,3  of  recent  date,  but  the  one  given  here,  which  is  based  on  Lin- 
naeus' grouping  by  Dr.  Sharp,  is  by  far  the  simplest. — F.  V.  T.] 


I.  Rkyncota? 

The  lower  lip  forms  a  long  thin  tube  that  can  be  turned  back  (rostrum), 
and  within  which  the  setaceous  mandibles  and  maxillae  are  situated  ;  the 
first  thoracic  segment  is  not  united  with  the  two  posterior  ones  ;  the 
anterior  wings  are  usually  leathery  as  far  as  the  centre. 


(a)  Rhynchota  aptera  s.  parasitica. 
Fam.  Pediculidce  (Lice). 

The  lower  lip  is  transformed  into  a  projecting  rostrum  provided  with 
barbed  hooklets  in  which  the  hollow  extensile  sucker  (maxillae  and  man- 
dibles) is  situated  ;  no  wings  ;  no  metamorphosis  ;  only  simple  eyes  ;  the 
antennae  are  five-jointed,  the  feet  possess  hook-like  terminal  joints ;  the 
barrel  shaped  eggs  (nits)  are  deposited  on  the  hair  of  the  host. 

1  American  Naturalist,  xx.,  p.  808,  1886. 

2  "  Syst.  Zool.  Studien,"  5.  B.  Ak.  Wien.,  xci.,  1885,  Abth.  i.,  p.  374. 

3  [Usually   known    as    Hemiptera.       There    are    two   sub-orders,  Heteroptera   and 
Homoptera.     The  former  have  the  base  of  the  front  wings  coriaceous  ;  the  latter  have 
all  four  wings  membranous.     The  Homoptera  are  Aphides  or  Plant   Lice  and  Scale 
Insects  (Coccidte),  none  of  which  attack  man. — F.  V.  T.] 


PEDICULUS    CAPITIS 


395 


i.     Pediculus  capitis,  De  Geer,  1778. 

Male  i — 1-5  mm.  in  length,  female  i'8 — 2'o  mm.  in  length.  The 
colour  varies  from  light  grey  to  black  according  to  the  colour  of 
the  hair  of  the  human  race  upon  which  they  are  parasitic.  The 
abdomen  has  eight  segments,  of  which  the  six  central  ones  are 
each  provided  with  a  pair  of  stigmata.  The  thorax  is  as  broad  as 

the   abdomen.     Eggs    O'6  mm.   in   length;    about 

fifty    are   deposited    by    a    female    Head     Louse. 

The    young    can    propagate   when  eighteen    days 

old. 


The  head  louse  lives  especially  in  the  hairy  parts  of 
the  head  of  human  beings  ;  more  rarely  it  is  found  en 
other  hairy  parts  of  the  body.  It  is  spread  over  the 
entire  surface  of  the  globe,  and  was  present  in  America 
before  the  arrival  of  Europeans.  Quite  exceptionally 
it  is  said  that  it  bores  itself  deep  into  the  epidermis 
and  can  live  in  ulcers.  , 

[The  eggs  are  pear-shaped  and  are  attached  to  the  hairs  near  the  roots 
by  means  of  a  clasping  collar.  They  hatch  in  about  seven  days.  The  young 
are  like  the  adults  and  mature  in  a  month.  Its  general  colour  varies  with 


FIG.  251. — Mouth 
parts  of  Pediculus 
vestimenti.  After 
Denny  (enlarged). 


FIG.  252. — Ovum 
of  the  head 
louse,  70/1. 


FIG.  253. — Head  louse,  male,   15/1. 


FIG.  254. — Pediculus  vesti- 
menti, Burm.  15/1. 
Adult  female. 


that  of  its  host.  In  West  Africans  nearly  black,  in  Hindoos  dark  and 
smoky,  on  Chinese  and  Japanese  yellow,  on  Hottentots  orange,  on  South 
American  Indians  dark  brown  (Murray). — F.  V.  T.] 


396  THE   ANIMAL   PARASITES    OF    MAN 

2.     Pediculus  vestimenti,  Nitzsch,  1818. 

The  head  in  front  is  somewhat  rounded.  Antennae  longer  than 
in  the  head  louse  ;  2 — 3-5 — 4  mm.  in  length  ;  whitish-grey  ;  the 
abdomen  is  broader  than  the  thorax  ;  stigmata  as  in  P.  capitis. 
Eggs  0*7 — 0'9  mm.  in  length  ;  about  seventy  are  deposited. 

Pediculus  vestimenti  lives  on  the  neck,  throat  and  trunk  of  persons, 
and  the  clothing  next  the  body,  in  which  also  the  eggs  are  deposited.  The 
louse  of  so-called  pedicular  disease  (Pediculus  tabescentium]  is,  according  to 
Landois'  researches,  only  the  usual  Pediculus  vestimenti  ;  moreover,  many 
cases  of  phthiriasis  are  attributable  to  mites  or  fly  maggots. 

[This  parasite  has  often  been  a  great  pest  amongst  soldiers  during  long 
campaigns,  especially  amongst  the  Russians  during  the  Crimean  War. — 
F.  V.  T.] 

3.     Phthirius  inguinalis,  Redi,  1668. 
Syn.  :  Pediculis  pubis,  L. 

Male  0-8 — ro  mm.  in  length  ;  female  ri2  mm.  in  length  ;  colour 
greyish-white  ;  form  sub-quadrate  ;  the  two  posterior  pairs  of  legs 
are  strong ;  the  abdomen  has  nine  segments  and  six  pairs  of 
stigmata  ;  and  still  another  pair  of  stigmata  is  situated  between 


Fig.  255. — Phthirius  inguinalis,  Leach  (enlarged).  They  are  distinguished  by  the 
larger  tracheal  trunks  originating  from  the  stigmata. 

the  two  anterior  limbs.  Eggs  pear-shaped,  O'8 — 0*9  mm.  in  length, 
0*4 — o'5  mm.  in  breadth,  and  are  deposited  in  rows  of  about  ten 
on  the  hairs. 

Pediculus  pubis,  which  is  found  almost  exclusively  in  the  Caucasian 
race,  lives  on  hairy  parts  of  the  body,  but  hardly  ever  on  the  skin 
of  the  head  ;  the  pubic  region  is  its  favourite  place  of  abode.1 

1  Literature  of  the  Pediculida.  Landois,  L.,  "  Unters.  ub.  d.  a.  d.  Mensch.  schma- 
rotzend.  Pediculinen  "  (Z.  /.  w,  Z.,  1864,  xiv.-xv.,  p.  i  ;  1865,  pp.  32  and  494). — Graber, 
V.,  "  An.-phys.  Stud,  uber  Phthirius  inguinalis"  (ibid.,  1872,  xxii.,  p.  157). — Giebel, 
C.  G.,  "  Insecta  epizoa,  Lpzg.,  1874. — Piaget,  E.,  Les  p6diculines.  Leide,  1880;  Suppl 
Letde,  1885. — Artauld  de  Vevey,  St.,  "  Deux  cas  de  pediculose  accid.  et  intermitt.  chez 
I'komme  "  (C.  R.  soc.  biol.,  Paris,  1895,  No.  29,  p.  684). 


RHYNCHOTA    HEMIPTERA 


397 


[This  species  reproduces  more  rapidly  than  other  lice,  and  is  communicated 
much  more  freely.  The  eggs  are  often  laid  singly  attached  to  the  hairs  near 
their  apex. — F.  V.  T.] 

(b)  Rhynchota  hemiptera. 
Fam.  Acanthiada. 

Body  flattened,  antennae  four-jointed,  rostrum  three-jointed,  wings 
atrophied.  [In  hot  countries  some  bugs  acquire  wings. — F.  V.  T.] 

4.     Cimex  lectularim,  Merrett,  1667. 
^  Syn.  :  Acanthia  lectularia,  Fabricius,  1794. 

It  measures  4 — 5  mm.  in  length,  3  mm.  in  breadth  ;  brownish-red  ; 
eight  abdominal  segments.  The  female  deposits  fifty  whitish  eggs 
at  a  time  (ri2  mm.  in  length)  three  or  four  times  a  year  ;  the 
entire  development  up  to  complete  maturity  takes  about  eleven 
months. 

The  bed  bugs  live  in  the  cracks  and  fissures  of  human  habitations, 
under  carpets,  behind  pictures,  in  furniture,  bedsteads,  &c.  ;  hidden  during 
the  day.  they  attack  persons  at  night  to  suck  their  blood.  The  alkaline 


FIG.  256. — Head  of  the  bed  bug  from  the  ventral  surface  •  a,  the  rostrum  ;  b 
the  antenna  ;  and  c,  the  eyes.  70  i. 

secretion  of  the  salivary  glands  dropped  into  the  wound  around  the  separate 
bites  causes  the  so-called  "  wheals." 

The  bed  bugs  were  known  in  bygone  days  by  the  Greek's  (*ap«r)  and 
tho  Romans  (cimexX  They  were  fir^t  mentioned  from  Strasbourg  in  the 
Eleventh  Century,  and  England  about  1500. 

[The  bed  bug.  can  migrate  from  one  house  to  another  ;  this  especially 
takes  place  when  a  house  is  uninhabited.  They  escape  from  windows 
and  pass  along  walls,  water  pipes  and  gutters,  and  so  reach  adjoining 
houses.  This  noxious  pest  accompanies  man  wherever  he  goes  ;  ships  and 
trains  become  infested,  especially  the  former. 


398  THE    ANIMAL    PARASITES    OF    MAN 

A  characteristic  feature  in  this  animal  is  the  peculiar  odour  it  produces, 
like  many  others  in  the  same  group  of  insects.  This  odour  comes  from 
a  clear,  oily,  volatile  liquid  secreted  by  glands  in  various  parts  of  the 
body.  Although  the  normal  food  is  man's  blood,  the  bed  bug  can  subsist 
upon  moist  wood,  dust  and  dirt  that  collects  in  crevices  in  floors,  walls, 
furniture,  &c.  The  puncturing  mouth  consists  of  a  fleshy  under  lip, 
within  which  lie  four  thread-like  hard  filaments  which  pierce  the  flesh, 
the  blood  being  drawn  up  through  the  beak. 

The  eggs  are  oval,  white,  with  a  projecting  rim  around  one  end  ; 
they  are  laid  in  cracks  and  crevices  in  batches  of  from  twelve  to  fifty . 
The  egg  stage  lasts  from  seven  to  ten  days.  The  larval  stage  so  gradually 
passes  into  the  adult  that  one  scarcely  notices  the  change  ;  during  its 
growth  the  skin  is  cast  five  times,  and  at  the  change  the  little,  wing- 
pads  are  seen,  showing  that  the  adult  stage  is  reached.  The  young 
larvae  are  at  first  pale  yellowish- white.  Although  eleven  weeks  is  said  to 
be  necessary  for  their  development,  the  stages  may  be  gone  through  much 
more  rapidly  ;  Howard  and  Marlatt 1  give  seven  weeks  in  some  instances. 
It  seems  pretty  certain  that  these  Cimex  only  take  one  meal  of  blood 
between  each  moult  and  another  preceding  egg  laying. — F.  V.  T.] 


5.  Cimex  ciliatus,  Eversmann,  1841. 

3*3  mm.  in  length,  yellowish-red,  thickly  covered  with  hair ; 
indigenous  in  Russia  (Kasan). 

6.  Cimex  rotundatus,  Signoret,  1852. 

Somewhat  larger  than  the  ordinary  bed  bug  ;  brownish-red  in 
colour,  legs  yellow.  On  the  Island  of  Reunion,  probably  like  the 
former,  only  a  variety  of  Cimex  lectularius.2 

Fam.  Reduviidce. 

Head  long,  narrowed  behind  into  a  neck  ;  eyes  large,  prominent  ;  rostrum 
thick  and  curved  ;  antennae  moderately  long,  slender  at  the  tip  ;  legs  long 
and  stiff  ;  carnivorous. 

[7.     Conorhinus  sanguisuga,  Lee.  (the  Blood-sucking  Cone-nose). 

This  bug  is  also  known  as  the  Texas  or  Mexican  Bed  Bug, 
also  as  the  .Big  Bed  Bug.  It  is  particularly  troublesome  in  the 
Mississippi  Valley  in  bedrooms.  The  bite  is  very  severe  and 

1  "Household  Insects."  Howard  and  Marlatt,  Bull.  No.  4  (N.S.)  U.S.  Dept. 
Agriculture,  p.  37,  1896. 

'2  Landois,  L.,  " Anat.  v.  Cimex  lectularius  "  (Z.  /.  w.  Z.,  1868,  xviii.,  p.  206  ;  1869, 
xix.,  p.  206). — Eversmann,  E.,  "  Qucedam  insectorum  species  novce  "  (Bull.  soc.  Imp. 
d.  natur.  Moscou,  1841,  xiv.,  p.  351). — Signoret,  V.,  "  Notice  sur  quelq.  hemipt.  nouv." 
(Ann.  soc.  entomol.,  France,  1852,  x.,  p.  539). 


CONORHINUS    RUBROFASCIATUS  399 

results  in  more  pronounced  swelling  and  inflammation  than  that 
of  the  Cimex.  Normally  this  genus  feeds  upon  the  blood  of 
mammals  and  insects.  Its  fondness  for  human  blood  appears  to 
be  quite  a  new  habit,  and  appears  limited  to  the  mature  insect 
only.  It  is  nearly  an  inch  long,  flat,  head  very  narrow  and  long, 
the  rostrum  short  and  thick.  In  colour  it  is  dark  brown  with  pink 
markings.  They  are  fully  winged  when  adult,  and  they  fly  with 
ease,  entering  houses  on  the  wing,  especially  being  attracted  by 
lights  in  windows  ;  they  also  run  swiftly.  Like  the  bed  bug  they 
conceal  themselves  during  the  day  and  come  out  at  night  and  bite 
the  sleeper.  The  effect  of  the  bite  is  very  varied,  but  as  a  rule 
a  sore,  itching  wound,  accompanied  by  burning  pain  and  swellings, 
which  may  extend  over  a  good  deal  of  the  body,  occur.  A 
specific  poison  is  undoubtedly  injected  into  the  puncture  ;  but  no 
doubt  serious  results  are  also  due  to  the  beak  being  contaminated 
through  the  insects  feeding  upon  foul  carrion.  Mr.  Lembert,  when 
bitten  by  a  Conor hinus  sp.  (?)  on  the  Pacific  Slope,  exhibited  the 
following  symptoms  :  An  itching  sensation  extending  up  the  leg, 
large  blotches  manifesting  themselves  on  the  upper  part  of  the 
limb  and  extending  up  to  the  hands  and  arms  ;  his  lips  swelled 
and  the  itching  and  swelling  extended  over  the  head  ;  there  was 
also  much  nausea.  Similar  results  are  recorded  from  other  regions.1 
The  eggs  of  the  C.  sanguisuga  are  at  first  white,  then  become 
yellow,  then  pink  ;  the  young  hatch  in  twenty  days.  There  are 
two  larval  and  two  pupal  stages,  the  latter  showing  wing-pads. 
The  eggs  are  laid  and  the  young  feed  out  of  doors,  chiefly  upon 
insects.  It  is  particularly  abundant  in  April  and  May  indoors. 

8.     Conorhinus,  sp.  novum  (the  Monster  Bug). 

Another  species ;  acts  in  a  very  similar  way  in  California,  the 
bite  being  very  poisonous. 

q.     Conorhinus  rubrofasciatus,  De  Geer2  (the  Malay  Bug). 

This  large  "bug  attacks  man  in  Malay.  It  is  recorded  as 
inflicting  "  a  very  nasty  sting,  which  is  done  by  the  huge  proboscis." 
Acute  pain  and  inflammation  follow  in  a  few  minutes.  In  one 
case  the  whole  leg  became  swollen.  This  species  occurs  in  Mada- 
gascar, Sierra  Leone,  Ceylon,  India,  China,  Philippines,  &c. 


1  "  Household  Insects,"  p.  42. 

2  First  Report  Economic  Zoology,  p.   130,   1903. — F.  V.  T. 


400  THE   ANIMAL    PARASITES    OF   MAN 

10.     Conorhinus  renggeri,  Herr-Schaff  (the  Great  Black 
Bug  of  Pampas). 

This  large  black  bug  is  mentioned  by  Darwin,1  who  states  as 
follows:  "At  night  I  experienced  an  attack  (for  it  deserves  no  less 
a  name)  of  the  Benchuca,  a  species  of  Reduvius,  the  Great  Black 
Bug  of  the  Pampas.  It  is  most  disgusting  to  feel  soft  wingless 
insects,  about  an  inch  long,  crawling  over  one's  body.  Before  suck- 
ing they  are  quite  thin,  but  afterwards  they  become  round  and 
bloated  with  blood,  and  in  this  state  are  easily  crushed.  One 
which  I  caught  at  Iquique  (for  they  are  found  in  Chili  and  Peru) 
was  very  empty.  When  placed  on  a  table,  and  though  sur- 
rounded by  people,  if  a  finger  was  presented,  the  bold  insect 
would  immediately  protrude  its  sucker,  make  a  charge  and,  if 
allowed,  draw  blood.  No  pain  was  caused  by  the  wound.  It 
was  curious  to  watch  its  body  during  the  action  of  sucking,  as 
in  less  than  ten  minutes  it  changed  from  being  flat  as  a  wafer  to 
a  globular  form.  This  one  feast,  for  which  the  Benchuca  was 
indebted  to  one  of  the  officers,  kept  it  fat  during  four  whole 
months  ;  but  after  the  first  fortnight  it  was  quite  ready  to  have 
another  suck."  Mr.  Kirby2  also  refers  to  this  species. 

ii.     Conorhinus  variegatus  (Variegated  Cone-nose). 

Occurs  in  Florida  in  houses,  and  chases  bugs  (Cimex)  and  flies ; 
not  definitely  known  to  bite  man. 

12.     Conorhinus  nigrovarius. 

This  species  occurs  in  South  America.  It  is  one  of  the  forms 
known  as  Bichuque.  Its  bite  makes  a  troublesome  swelling. 

13.  C.  protractus  also  attacks  man  in  Utah.3     It  has  been  called  the 

"  Big  Bed  Bug." 

14.  Reduvius  personatus,  Linne  ;  Reduvius  personatus,  Leconte,  1855. 

European,  but  also  found  in  the  United  States.  The  bite  causes 
intense  pain.  It  bites  when  caught  or  handled,  but  does  not  seem 
to  do  so  voluntarily.  Swelling  and  irritation  result  which  may  last 

1  "A  Naturalist's  Voyage  "  (Voyage  of  the  Beagle),  p.  330,  1888,  Charles  Darwin. 

2  "Text  book  of  Entomology,"  p.  205,  1885. 

<^i  3  «  The  j^g  ge(j  gug  Of  the  par  West,"  Bull.  18  (N.S.),  1898",  p.  lor,  U.S.  Depart 

ment  Agriculture. 


CORISCUS,    RASAHUS,   MELANOLESTES  4OI 

a  week  and  may  even  cause  death.1  In  1899  it  was  very  abun- 
dant at  Washington  and  elsewhere  ;  other  species  occurred,  and  so 
no  definite  opinion  existed  as  to  the  actual  biter,  but  some  people 
took  R.  personatus  actually  biting.  It  was  first  described  as  a 
parasite  of  man  in  America  by  Walsh  and  Riley.2 

A  popular  name  for  this  bug  is  the  Wheel  or  Masked-bug — a 
black  insect,  three-fourths  of  an  inch  long.  The  larva  of  this 
bug  is  carnivorous  and  covers  its  body  with  dust  so  as  to  conceal 
itself  from  its  prey.  The  adult  is  active  on  the  wing. 

15.     Coriscus  subcoleoptratus,  Kirby,  1837. '* 

Nabicula  subcoleoptrata,  Kirby,  1837  ;  Nabis  subcoleoptratus,  Reuter,  1872  ; 
Coriscus  subcoleoptratus,  Stal,  1873. 

N.  United  States.  Howard  was  bitten  by  one  between  the 
fingers — the  pain  was  intense,  like  a  needle  prick,  but  the  swelling 
was  small.  No  other  case  known. 


16.     Rasahus  biguttatus,  Say,  1831. 

Pirates  biguttatus,  Stal,  1862  ;  Callisphodrus  biguttatus,  Stal,  1866  ;  Rasahus 
biguttatus,  Stal,  1872. 

Common  in  S.  United  States,  and  found  in  Cuba,  Panama  and 
Para,  &c.  Known  as  the  Two-spotted  Corsair  on  account  of  the 
great  spot  on  the  hemielytra.  Frequently  found  in  houses  where 
it  chases  the  bed  bug.  It  also  bites  man  frequently.  From 
1869  Walsh  and  Riley  placed  it  amongst  the  parasites  of  man. 
In  United  States  Davidson4  is  of  opinion  that  all  cases  attributed 
to  spider  bites  are  due  to  this  insect. 

17.     Melanolestes   morio,  Erichson  (1848),  Non-WTalker. 

Pirates  morio,  Erichson,  1848;  Melanolestes  morio ,  Stal,  1866;  Pirates 
picipes,  Herrich-Schaffer,  1848  ;  Melanolestes  picipes,  Howard,  1900. 

Guiana  and  Mexico  and  E.  and  S.  United  States.  Length  20 
mm.  ;  hides  under  stones  and  logs  during  daylight  and  flies  at 

1  "  Insects  to  which  the  name  '  Kissing-bug  '  became  applied  during  the  summer 
of  1899,"  Bull.  No.  22  (N.S.),  p.  24,  1900,  U.S.  Department  Agriculture. 

2  American  Entomologist,  i,  p.  84-88,  1869. 

3  "  Sur   la    Piquee    de  quelques   Hemipteres"    Arch,   d  Parasitohgie,    p.  145,  1902, 
R.  Blanchard. 

*  "  So-called  Spider  Bites  and  their  treatment,"  Therapeutic  Gazette,  February  19, 
1875- 
26 


402  THE   ANIMAL   PARASITES   OF   MAN 

night.  Attracted  by  lights  into  houses.  Very  abundant  in  1899 
at  Washington.  Howard  cites  cases  where  it  was  proved  to  bite 
man. 

18.     Melanolestes  abdominalis,  Herrich-Schaffer  (1848). 

Pirates  abdominalis,  Herrich-Schaffer ;  Melanolestes  abdominalis,  Uhlert 
1875- 

Allied  to  the  former ;  some  say  similar,  but  can  be  told  by 
the  shorter  wings  on  the  female.  It  occurs  in  the  same  localities 
as  M.  morio. 

Fam.  Lygczidce. 

Scutellum  short  ;  antennae  four-jointed  ;  ocelli  present  ;  membranous 
part  of  hemielytra  with  never  more  than  five  nervures.  Nearly  all  vege- 
table feeders.  x\  few  are  recorded  here  as  biting  man. 


19.     Lyctocoris  campestris,  Fabricius. 

Acanthia  campestris,  Fabricius. 

(Lyctocoris  domesticus.) 

Rare  in  habitations,  lives  on  human  blood.  Found  by  Blan- 
chard  in  a  bed  at  an  hotel  at  Liverpool.  The  bite  is  undoubtedly 
worse  than  that  of  Cimex.  Cosmopolitan.  In  colour  it  is  ferruginous, 
shining,  legs  testaceous;  hemielytra  slightly  shorter  and  narrower 
than  the  abdomen  ;  membranous  portion  transparent,  the  apex 
broadly  fuscous.  Length  3*8  to  4*8  mm. 


20.     Rhodinus  prolixus,  Stal,  1859. 

Sometimes  attacks  man,  and  the  bite  is  very  painful.  It  is 
25  mm.  long  and  8  mm.  broad,  and  occurs  in  Colombia.  It 
is  found  also  in  Cayenne  and  Venezuela.  This  like  other  species 
is  known  in  South  America  as  Bichuque  or  Benchuca. 

A  few  other  unimportant  species  are  also  recorded  as  biting  man, 
such  as  Harpactor  cruentas,  in  the  South  of  France  ;  Eulyes 
amcena,  from  Borneo  and  Java ;  Arilus  carinatus  (Forster),  from 
Brazil.  The  latter  appears  to  be  the  same  as  the  Acanthia 
serratus,  Fabricius. — F.  V.  T.] 


COLEOPTERA.       DIPTERA  403 

II.  Coleoptera. 

The  larvae  of  beetles,  similarly  to  those  of  some  other  Arthropoda  (myriapods 
and  the  larvae  of  gnats),  have  sometimes  been  observed  in  man  as  purely 
accidental  guests.  In  one  case  or  another,  such  accounts  may  have  origi- 
nated through  a  decided  mistake  of  the  observer.  Thus  English  doctors 
report  the  presence  of  the  larvae  of  Blaps  mortisaga  in  the  stools  of  human 
beings,  Sandberg  of  the  larvae  of  Agrypnus  murinus  in  his  ten-year-old 
son,  and  Blanchard  mentions  the  larva  of  a  beetle  that  was  vomited  by 
a  child.  All  these  cases,  however,  do  not  represent  actual  parasitism, 
although  there  are  beetles  living  parasitically.1 


[Silvanus    surinamensis,    Linnaeus    (the    Saw-toothed  Grain   Beetle). 

Taschenberg  records  this  beetle  as  having  invaded  some  sleep- 
ing apartments  adjoining  a  brewery  where  stores  were  kept,  and 
annoying  the  sleepers  at  night  by  nipping  them  when  in  their  beds. 

This  beetle  is  common  in  many  parts  of  the  world  amongst 
groceries,  corn,  meal,  seeds,  dried  fruits,  &c.  '  It  is  about  one- 
tenth  of  an  inch  long,  much  flattened  and  chocolate  -  brown  in 
colour.  The  thorax,  has  two  shallow  grooves  and  bears  six  minute 
teeth  on  each  side.  The  jaws  are  strong,  but  the  bite  cannot  be 
very  serious. — F.  V.  T.] 


III.  Diptera. 
(a)  Aphaniptera  (Fleas). 

Wingless,  the  thoracic  rings  not  amalgamated  ;  antennae  three-jointed  ; 
legs  very  powerful  ;  abdomen  with  nine  segments.  The  mandibles  trans- 
formed into  serrated  puncturing  organs,  which  are  situated  in  the  split 
sheath  of  the  rostrum,  originating  from  the  labrum  ;  the  maxillae  are 
laminated  and  have  palpi. 

i.     Pulex  irritans,  L.,  1758. 

Maies  2—2-5  mm.  in  length,  females  about  4  mm.  ;  reddish  or 
dark  brown  ;  head  without  bristles  ;  thoracic  and  abdominal  rings 

1  [Dr.  Daniels  has  sent  me  a  small  coleopterous  larva  found  in  an  abscess  on  a  man 
in  British  Guiana.  —  F.  V.  T.] 

•Cobbold  T.  Sn.,  "  On  Blaps  mortisaga  as  a  Human  Parasite  (Bnt.  Med.  Journ., 
1877  i  P.  420).—  Sandberg,  G.,  "  Et  Mfcelde  af  Coltoptlrlarvers  tilhold  i  tarmkanalen 
hoi  et  menneske"  (Entom.  Tidskrift.,  Stockh.,  1890,  p.  77.:  C.  /.  B.  u  P.,  1890  viii., 
p  Ig2)  —Blanchard,  R.,  "  Sur  ime  larve  de  Colfopt&re  vomie  par  un  enfant  au  Senegal 

—  "  rs.  Kafer       C.    .  B. 


p    Ig2)  —ancar,      .,         ur  ime   arve          o 

(Bull.  soc.  entom.,  France,  1893,  p.  156).—  Brandes,  G.,   "  Ueb.  paras.  Kafer      (C.  /.  B.. 

P.  u.  I.,  1896,  xx.,  p.  297). 


404 


THE   ANIMAL    PARASITES    OF   MAN 


of  bristles  on  the  dorsal  aspect,  and  small  hairs  directed  back- 
wards at  the  posterior  margin.  The  barrel-shaped  white  eggs  are 
deposited  in  cracks  in  the  boards,  sweepings,  spittoons,  &c.  ;  they 
produce  legless  larvae  consisting  of  fourteen  segments,  which,  after 
about  eleven  days,  are  transformed  into  pupae  ;  after  another 
eleven  days  the  flea  emerges. 


FIG.  257. — Pulex  irritans.      14/1 


FIG.  258.  —  Larva  of 
flea,  enlarged.  (After 
Railliet.) 


^  259. — Pulex  serraticeps.     22/1. 


Fleas  live  in  human  dwellings  all  over  the  worid.  and  periodically 
pass  on  to  persons  to  suck  their  blood.  They  may  deposit  their  eggs  on 
very  uncleanly  individuals,  and  even  undergo  development,  therefore  it  is 
possible  to  find  larvae  and  pupae  on  such  persons. 

The  dog  flea,  Pulex  serraticeps,  is  easily  distinguished  from  the  flea  of 
man  by  the  large  thick  bristles  on  the  posterior  margin  of  the  first 
thoracic  ring  (fig.  259). 


SARCOPSYLLA  PEN-fiTRANS 


405 


2.     Sarcopsylla  penetrans  (L.),  1758  (Jigger,  Chigoe). 


About  i— 1-2  mm.  in  length  ;  brown  in  colour.  The  males  only 
occasionally  visit  man  to  bite  ;  the  fertilised  female,  on  the  other 
hand,  bores  into  the  skin  with  her  head,  particularly  about  the  toes 
of  the  host,  and  then  attains  considerable  dimensions.  The  eggs 
develop  on  the  soil  with  a  metamorphosis  similar  to  that  of  the 
common  flea. 


FIG.    260. — Sarcopsylla    penetrans,    young 
female,  highly  magnified.     (After  Moniez.) 


FIG.  261. — Sarcopsylla  penetrans, 
older  female,  enlarged.  (After 
Moniez.) 


The  sand-flea  (nigua)  particularly  infests  Central  and  South  America,  and, 
in  1873,  was  carried  by  ships  from  Brazil  to  the  West  Coast  of  Africa. 
In  a  comparatively  short  time  it  has  become  disseminated  throughout  Africa 
and  has  also  appeared  in  Madagascar  ;  recently  also  it  has  been  reported 
from  China. 

Besides  attacking  man  it  also  settles  on  mammals,  for  instance,  on 
dogs,  pigs,  &c.  According  to  Jullien  the  wound  or  little  swelling  caused 
by  the  female  has  no  particular  significance,  as  children  infested  with  ten 
or  eleven  sand-fleas  quietly  proceeded  with  their  games.  It  will  be  under- 
stood, however,  that  the  wound  easily  affords  the  opportunity  for  the 
setting  up  of  inflammation  or  even  septic  processes,  as  is  the  case  in 
any  kind  of  wound.1 
• 

1  Taschenberg,  O.,  "  Die  Flohe  .  .  .  monogr.  dargrstellt."  Halle,  1880. — Bergh, 
R.,  "  Die  Flohlarue  als  Pseudoparasit  d.  Mensch."  (Monatsh.  f.  pr.  Dermatologie,  1885, 
iv.,  p.  209). — Jullien,  J.,  "  La  chique  sur  la  cote  occidentale  d'Ajrique  "  (Bull  soc.  tool., 
France,  1889,  p.  93). — Blanchard,  R.,  "  Quelq.  mots  sur  la  Chique"  (Bull.  soc.  zool. 
de  France,  1889,  xiv.,  p.  95). — Blandfoord,  W.  H.  F..  "  The  Chigoe  in  Asia  "  (Entomol. 
Monthly  Mag.,  1894,  v.,  p.  228). — Blanchard,  R.,  Pres.  de  la  chique  a  Madagascar'9 
(Arch,  de  Paras.,  1899.  "•>  P-  627)- 


406  THE   ANIMAL    PARASITES    OF    MAN 

[The  chief  genera  and  species  of  British  Pulicidce  may  be  tabu- 
lated as  follows  :— 

(1)  Pulex  :    Eyes  distinct. 

(2)  Hystrichopsylla  :    Densely  spinose  cheeks    and   clypeus.     No  eyes,   or 

eyes  indistinct. 

(3)  Typhlopsytta  :       Body    narrow    and    elongated.       No    eyes,    or    eyes 
indistinct. 

(1)  Pulex. 

No  prothoracic  posterior  comb  .  .  .  .  .  .  .  .      irritans. 

Posterior  comb  present. 

Head  without  black  spines. 

Prothoracic  comb  with  twenty-six  teeth         . .  .  .      gallince. 

Prothoracic  comb  with  eighteen  teeth  .  .  .  .      fasciatus. 

Head  with  black  spines. 

Cheeks,  &c.,with  six  or  seven  black  spines  on  each  side     canis. 

(2)  Hystrichopsylla. 

Cheeks  and  clypeus  densely  spinose  . .          .  .     obtusiceps. 

(3)  Typhlopsytta. 

Comb  only  on  posterior  margin  of  pronotum. 

Four  genal  spines  . .  .  .  .  .  .  .  .  .      musculi. 

Three  genal  spines          . .          . .          .  .          . .          .  .      assimilis. 


3.     Sarcopsylla  gallinacea,  West  wood  (The  Chigoe  of  Fowls). 

This  flea  is  a  native  of  Ceylon  and  N.  America.  It  lives  on 
the  fowl  chiefly,  attacking  the  neck  and  around  the  eyes.  Speci- 
mens were  sent  me  from  Texas,  where  they  not  only  attack 
poultry  but  also  children,  the  latter  somewhat  severely.  It  also 
occurs  on  cats. 


4.    Pulex  serraticeps,  Gervaise  (The  Common  Cat  and  Dog  Flea). 

In  the  eastern  cities  of  America  the  cosmopolitan  dog  flea  is 
the  species  that  overruns  houses.  Man  is  badly  bitten  by  this 
species  in  most  parts  where  it  occurs.  The  eggs  are  deposited 
amongst  dust,  clothes,  &c.,  and  hatch  out  in  fifty  hours  amongst 
the  dogs'  and  cats'  hairs.  As  they  are  not  fastened  to  the  hairs 
they  fall  off.  The  larvae  live  seven  days  and  then  spin  a  cocoon 
amongst  the  dust  and  dirt.  They  remain  in  the  cocoons  eight 
days.  The  times  are  variable,  however,  for  Howard  and  Marlatt 
show  that  the  eggs  hatch  in  one  day  and  the  larvae  commence 
to  spin  in  from  seven  to  fourteen  days  after  hatching,  and  the 
flea  appeares  five  days  later.  The  changes  thus  observed  in 
Washington  agree  with  those  observed  by  Simmons  in  Calcutta. 


MOSQUITOES  407 

5.     Pulex  fasciatus,  Bosc. 

This  flea  is  also  found  on  the  rat  and  will  attack  man.  It 
has  eighteen  teeth  on  the  prothoracic  comb  and  no  black  spines 
on  the  head. 

6.     Pulex  pallipes  is  another  species  found  on  the  rat  and  man. 
7.     Typhlopsylla  musculi,  Duges  (The  Rat  Flea). 

In  the  genus  Typhlopsylla  the  body  is  narrow  and  elongated, 
and  on  the  under  side  of  the  head  are  numerous  chitinous  bristles, 
and  also  on  the  pronotum.  This  rat  flea  is  also  found  on  the 
vole  ;  it  is  dark  yellowish-brown  and  the  body  attenuated  in  front, 
and  there  is  a  distinct  comb  on  the  posterior  margin  of  the  pro- 
notum ;  the  legs  have  very  few  hairs,  femora  bare  and  curved  ; 
tibiae  with  black  bristles  ;  four  spines  on  the  genae. 

An  allied  species,  T.  assimilis,  Taschenberg,  occurs  on  mice, 
shrews,  moles,  and  voles  ;  it  has  only  three  genal  spines. — F.  V.  T.] 


SYSTEMATIC,  ANATOMICAL,  AND  BIOLOGICAL  REMARKS  ON 

MOSQUITOES. 

Mosquitoes  Nematocera  form  one  of  the  four  sub-orders  of  the  Diptera, 
and  are  divided  into  numerous  families,  of  which,  however,  only  the 
CulicidcB  are  of  interest  to  us  here.  The  head  is  small,  the  facetted  eyes 
are  placed  laterally,  but  there  are  no  accessory  eyes  (ocelli).  In  front 
of  the  eyes  are  situated  the  comparatively  long  antennae,  the  differences 
of  which  strongly  mark  the  distinction  of  sex.1 

The  antennae  are  composed  of  fifteen  or  sixteen  segments.  In  the  male 
they  are  covered  with  long  whorl-like  hairs,  while  in  the  female  the 
antennal  hairs  are  short — differences  that  are  perceptible  even  with  the 
naked  eye.2  The  proboscis,  which  is  longer  than  the  antennae,  protrudes  from 
the  inferior  aspect  of  the  head  and  is  composed  of  the  following  parts  (figs.  264 
and  265)  :  Two  grooved  half  tubes,  facing  one  another,  of  which  the  upper  one 
is  the  upper  lip  (labium),  and  the  lower  one  the  lower  lip  (labrum),  which 
represents  a  pair  of  coalesced  maxillae.  Within  the  tube  formed  by  the 
labrum  and  labium  are  the  mandibles  and  maxillae,  transformed  into  instru- 
ments for  piercing,  and  a  single  puncturing  organ,  the  hypopharynx.  On 
the  right  and  left,  next  to  the  proboscis,  are  placed  the  straight  five- 


1  [This  is  by  no  means  always  the  case  ;  in  the  genera  Deinocerites,  Wyeomyia, 
Limatus,  Theobald,  and  in  Sabethes,  Robineau  Desvoidy,  they  are  nearly  the  same 
in  both  sexes. — F.  V.  T.] 

-  [This  is  not  always  the  case,  vide  previous  note. — F.  V.  T.I 


408 


THE    ANIMAL    PARASITES   OF    MAN 


jointed  palpi,  the  final  joint  of  which  is  thickened  in  the  male.1  In  biting, 
the  labrum,  which  is  swollen  at  its  free  end,  is  not  introduced  into  the 
wound  like"  the  other  mouth-parts,  but  is  bent  backwards.  The  labium 
and  hypopharynx  push  direct  into  the  skin  ;  the  maxillae  and  mandibles, 
however,  which  are  needle-like  and  serrated  at  the  tips,  penetrate  with  a 


FIG.   262. — Head  of  a  male  (a)  and  of  a  female  (b)  Anopheles  ;  slightly  enlarged. 
(After  Giles.) 


FIG.  263. — Head  of  a  male  (a)   and  of   a  female  (b)  Culex.     (After  Giles.' 


saw-like  movement.  [The  swollen  free  end  of  the  labrum  really  means  the 
Idbellce^  two  articulated  pieces,  supposed  by  some  to  be  the  labial  palpi.  In 
most  species  the  mandibles  are  not  serrated  at  their  ends. — F.  V.  T.]  The 

1  [This  is  only  so  in  Anophelina  and  in  the  genus  Theobaldinella,  Neveu-Lemaire, 
Grabhamia,  Theobald,  Acartomyia,  Theobald,  &c.  In  true  Culex  and  many  other 
genera  the  male  palpi  are  pointed. — F.  V.  T.] 


MOSQUITOES 


409 


saliva  is  introduced  into  the  wound  through  the  lumen  of   the  hypopharynx, 

while  the  blood  is  sucked  up  by  the  mosquito  in  the  groove  of  the  labium. 

The    three    thoracic    segments    are    soldered    together.      The    central    one 


md. 
h. 

mx. 


FIG.    264. — Mouth-parts  of  Anopheles  claviger*    (after  Grass!) ;    h.,  hypopharynx 
md.,  mandible  ;    mx.,  maxilla  :    u.L,  upper  lip  ;    l.L,  lower  lip  ;    p..  palpi. 


Ar. 


hy. 


(a) 


md. 


FIG.  265. — Anopheles  maculipennis  (after  Nuttall  and  Shipley).  Transverse  section 
through  the  proboscis  of  a  female  (a)  and  a  male  (b) ;  hy.,  hypopharynx,  with  duct  of 
the  salivary  gland;  m.,  muscles;  md.,  mandibles;  mx.,  maxillae;  /.,  labium;  /./., 
labrum. 

carries  the  membranous  wings  on  the  sides  of  the  dorsal  surface ;  the  posterior 
somite  carries  the  small  halteres  (rudimentary  posterior  wings).  There  are 
three  pairs  of  long  slender  legs  on  the  lower  side. 

1  [This  should  read  Anopheles  maculipennis,  Meig.  ;   there  was  no  type  of  A.  claviger. 
— F.  V.  T.] 


410 


THE    ANIMAL    PARASITES    OF    MAN 


The  abdomen  has  no  limbs,  is  composed  of  eight  distinct  segments  ; 
the  sexual  and  anal  orifices  are  at  the  posterior  end,  the  stigmata  on  the 
sides.  The  intestinal  canal  (fig.  266)  is  composed  of  three  principal  divi- 
sions ;  the  anterior  part  reaches  as  far  as  the  front  pair  of  legs,  and  con- 
sists of  the  oesophagus,  which  is  provided  with  two  small  lateral  diver ticula. 
[At  the  commencement  of  the  oesophagus  are  usually  three  diverticula,  which 
vary  in  size  ;  they  contain  air,  food  and  bacteria. — F.  V.  T.]  The  mid-gut 
reaches  as  far  as  the  fifth  and  sixth  abdominal  ring ;  in  front  it  is  thin, 

and  has  numerous  small  supra-oesophageal  gan- 
glia ;  the  posterior  part  is,  however,  more  dilated. 
Five  Malpighian  tubes,  the  excretory  organs,  dis- 
charge at  the  place  where  the  mid-gut  passes  into 
the  terminal  gut. 

The  pair  of  salivary  glands  have  one  common 
excretory  duct  leading  into  the  hypopharynx. 

The  glandular  body,  situated  in  the  thorax, 
consists  of  three  slightly  serpentine  tubules  at 
each  side,  the  dorsal  and  ventral  tubes  being 
long,  the  central  one  shorter.  The  above-named 
characteristics  apply  to  both  genera  Culex  and 
Anopheles.  The  difference  consists  in  various 
peculiarities  in  form.  The  genus  Culex  is 
smaller,  Anopheles  larger.  [In  Anopheles  the 
ends  of  the  ducts  in  the  lobules  are  dilated, 
whilst  in  most  of  the  genera  the  ducts  are  the 
same  size  all  along.  The  lobules  may  bifur- 
cate, and  in  Psorophora  there  are  five  lobules. 
— F.  V.  T.]  The  legs  of  the  genus  Culex  are 
about  the  same  length  as  the  whole  body  ;  in 
Anopheles  they  are  double  that  length.1  In 
Anopheles  the  palpi  and  proboscis  are  of  equal 
length  ;  in  Culex  the  condition  is  different,  ac- 
cording to  sex.  In  the  male  the  palpi  are  longer 
than  the  proboscis  ;  in  the  female  considerably 
shorter  and  the  number  of  joints  diminished. 
The  venation  of  the  wings  exhibits  further 
points  of  differentiation,  as  also  their  adorn- 
ment, though  this  last  sign  is  not  by  any  means 
always  conclusive  ;  most  species  of  the  genus  Culex 
have  unspotted  wings,  whilst  those  of  Anopheles 
are  spotted.  More  important  is  the  fact  that 
in  Culex  the  abdomen  is  decorated  with  small 
scales,  similar  to  those  on  butterflies,  whereas 
there  are  small  bristles  on  the  abdomen  of 

Anopheles.  [This  cannot  be  said  to  be  a  character  by  which  an 
Anopheline  may  be  told  from  a  Culicine,  for  in  such  common  Anopheline 
genera  as  Cellia  and  Nyssorhynchus  we  get  plenty  of  scales  on  the  abdomen,  and 


FIG.  266. — Longitudinal 
section  of  an  Anopheles, 
showing  alimentary  canal 
(after  Grassi).  In  the  fore- 
part of  the  thorax  is  the 
salivary  gland  consisting  of 
three  tubules  ;  ventrally, 
the  suctorial  stomach  ex- 
tending into  the  abdominal 
cavity ;  the  stomach,  and 
at  the  posterior  end  of  the 
abdomen  the  Malpighian 
vessels. 


1  [This  is  certainly  not  always  the  case. — F.  V.  T.] 


MOSQUITOES 


in  Aldrichia  as  complete  a  scaly  coat  as  any  Culicine. — F.  V.  T.]  An  experienced 
observer  can,  however,  differentiate  the  two  genera  by  the  difference  in  size  and 
their  manner  of  resting.  When  settled  they  either  touch  the  resting  place  with 
all  the  legs  or  only  with  the  four  anterior  legs.  In  consequence  of  the  different 
length  of  the  legs,  the  body  of  Culex  approaches  the  resting  place  more  closely  ; 
moreover,  Culex  holds  the  abdomen  parallel  to,  or  at  an  acute  angle  to,  the 
resting  surface  ;  whereas  Anopheles  carries  the  abdomen  directed  upwards  (at  an 


FIG.   267. — Anopheles  maculipennis,  Meigen  (enlarged).     (After  Grassi.) 

angle  of  about  145°)  and  holds  the  head  down.  Both  genera,  however,  usually 
only  rest  on  the  four  anterior  legs,  and  then,  as  has  long  been  known, 
Culex  carries  the  third  pair  directed  towards  the  dorsum,  while  those  of 
Anopheles  hang  down. 

In  regard  to  the  differentiation  of  the  species,  I  must  refer  you 
to  the  special  literature,  and  content  myself  by  observing  that  about 
150  species  of  Culex  and  about  50  species  of  Anopheles  have  been 
described,  of  which  50  about  four  are  found  in  Europe.  [The  number  of 
known  Anophelines  now  is  at  least  90  species,  of  other  Culicidae  about 

580. F.  V.  T.]     According  to  our  present  knowledge  it  appears  that  the  entire 

genus  Anopheles  can  transmit  malaria  to  man  ;  this  observation  has  been  con- 
firmed in  Anopheles  claviger,  Fabr. ;  A.  maculipennis,  Meig.  ;  A.  bifurcatus,  L.  ; 
A.  superpictus,  Grassi  ;  A.  pseudopictus,  Gr.,  all  of  which  are  found  in  Italy,1 

1  Compare  Ficalbi,  E.,  "  Venti  spec,  di  zanzare  (Culicida;)  ital.  .  ."  (Bull. 
soc.  entom.  ital.,  1899,  'xxxi.  ;  ref.  in  Centr.  /.  Baht.,  Paras,  it.  Inf.,  1900,  xxviii., 
p.  397- 


THE    ANIMAL    PARASITES    OF    MAN 

Germany,  &c.,  as  well  as  in  the  Tropics.  Moreover,  in  A.  costalis,  Loew  ; 
A.  funestus,  Giles  (Africa);  A.  quadrimaculatus,  Say  (North  America),  and 
A.  rossii,  Giles;  the  latter  is  perhaps  identical  with  A.  superpictus,  Gr., 
as  well  as  with  A.  culicifacies  (India).  [Anopheles  maculipennis  and 
A.  claviger  are  the  same.  Certainly  neither  maculipennis  nor  bifurcatus  have 
been  found  in  the  Tropics.  Anopheles  quadrimaculatus,  Say,  is  the  same  as 
A.  maculipennis.  There  is  no  evidence  that  all  Anophelines  carry  malaria, 
but  there  is  much  to  show  that  certain  species  only  are  capable  of  so  doing  ; 
Rossii  will  not  do  so. — F.  V.  T.]. 

Everyone  is  aware  that  mosquitoes  swarm  at  sunset  in  fine  weather, 
and  at  that  time  seek  out  human  beings  and  other  warm-blooded  animals 
to  take  food.  In  this  regard,  however,  the  sexes  differ,  in  so  far  as  that 
it  is  almost  without  exception  that  the  females  only  suck  blood,  while 
the  males  subsist  on  the  juices  of  plants  (blossoms  or  fruits ').  After 
sucking,  and  when  night  has  fallen,  the  mosquitoes  find  a  place  of  refuge, 
for  which  purpose  they  utilise  the  grasses  or  foliage  of  trees  and  bushes, 
or  inhabited  or  uninhabited  rooms  of  houses,  also  cellars,  stables,  verandahs, 
&c.,  where  they  also  pass  the  day. 

[Some  mosquitoes  bite  in  the  daytime — Stegomyia  and  some  A  nophelines  ; 
some  bite  right  into  the  night,  as  Culex  fatigans  and  C.  pipiens. — F.  V.  T.]. 

The  period  required  for  digestion  varies  according  to  the  temperature. 
It  takes  two  days  in  summer,  and  may  take  up  to  ten  days  or  more  in 
cool  weather.  After  digestion  is  complete  more  food  is  taken  up,  this  being 
necessary  for  the  maturing  of  the  sexual  products. 

It  is  still  unknown  under  what  circumstances  copulation  takes  place'-  ; 
in  any  case,  sooner  or  later  the  females  are  fecundated,  and  when  the 
ova  have  become  mature,  and  the  season  is  not  too  far  advanced,  they 
seek  a  suitable  place  in  which  to  deposit  them.3  These  are  larger  or  smaller, 
permanent  or  temporary,  collections  of  standing  water,  pools,  puddles, 
lakes,  pits,  water  in  rain-water  barrels,  basins,  &c.  Nevertheless,  certain 
kinds  prefer  certain  waters  ;  thus  Anopheles  (claviger'}  maculipennis  and  several 
of  the  Culices  seek  stagnant  water  overgrown  with  swamp  vegetation  and 
decomposing  vegetable  matter  ;  A .  bifurcatus  and  certain  Culices,  clear  water 
with  some  vegetation  (such  as  fountains  and  the  lakes  in  gardens  and 
parks)  ;  Culex  pipiens  has  a  preference  for  rain-water  barrels,  even  though 
the  water  be  dirty  and  evil-smelling.  [I  have  found  the  larvae  of  Anopheles 
bifurcatus  living  in  great  numbers  in  ponds  and  lakes  completely  overgrown 
with  floating  water-weeds,  and  those  of  Culex  pipiens  in  liquid  manure. 

Sexual  Organs  of  the  Mosquito. — The  female  has  a  pair  of  ovaries,  opening 
into  a  single  tube,  by  the  ovarian  tubes  ;  into  the  single  tube  opens  a  duct 
coming  from  the  spermathecae.,  and  also  a  mucous  gland.  The  spermathecae 


1  Both  males  and  females  may  be  kept  alive  in  captivity  for  a  long  time  if  given 
fruits,  or  even  only  sugar  and  water. 

2  The  female  Culex  has  three   receptaculse  seminalis,   while    the  female  Anophele 
has  one  receptaculum  seminis. 

3 It  is  certain  that  the  females  perish  immediately  after  depositing  the  ova;  but 
this  dees  not  always  hold  good,  as  a  part  of  them  survive  for  a  few  days.  The  males 
die  soon  after  copulation. 


MOSQUITOES 


413 


store  up  the  male  cells.  The  male  organs  consist  of  two  testes  joined  by 
ducts  (vasa  deferentia)  to  the  ejaculatory  duct  formed  by  their  union. 
Each  vas  deferens  is  joined  by  a  short  tube  with  the  sac-like  vesicula 
seminalis. — F.  V.  T.]. 

There  is  also  a  difference  in  the  manner  in  which  Culex  and  Anopheles 
deposit  their  ova.  Culex  deposits  two  to  three  hundred  eggs  in  com- 
pact heaps  that  float  on  the  water,  and  in  which  the  eggs  stand  perpen- 
dicularly one  next  the  other;  whereas  Anopheles  maculipennis  deposits 
only  three  or  four  up  to  twenty  eggs,  united  in  short  rows  that  float  horizon- 
tally on  the  water  ;  the  eggs  of  A .  bifurcatus,  again,  are  arranged  in  star-like 
groups.  The  eggs  are  about  o-75  mm.  in  length,  and  assume  a  dark  hue 


— 


3 


FIG.   268. — Larva  of    Anopheles   maculi- 
pennis, Fabr.  (enlarged.)     (After  Grassi.) 


FK».  269. — Larva  of  Culex  (enlarged.) 
(After  Grassi.) 


soon  after  being  laid.  The  development  only  occupies  a  few  days.  The 
hatched-out  larvae  grow,  rapidly,  changing  their  integument  several  times  ; 
the  larvae  also  differ  in  the  various  genera,  though  they  are  very  similar  in 
form  (figs.  268  and  269). 

The  long  legless  larva  has  a  flattened  head,  a  fairly  broad,  rectangular,  or 
trapeziform  thorax,  on  which  there  are  bristles,  and  an  abdomen  distinctly 
segmented,  and  on  the  segments  of  which  there  are  also  lateral  bristles.  The 
situation  of  the  stigmata  marks  the  difference  between  the  two  genera.  Though 
in  both  genera  the  stigmata  are  at  the  posterior  end  and  on  the  dorsal  surface, 
they  are  in  Anopheles  close  to  the  surface  of  the  body  ;  in  Culex,  however, 
they  are  on  the  free  end  of  a  long  tube  (syphon). 

The  position  of  the  larva  in  the  water  also  differs.  The  larva  of  Anopheles 
lies  almost  horizontally  beneath  the  surface  of  the  water,  the  posterior  border 
of  the  penultimate  abdominal  segment,  upon  which  the  stigmata  are  situated, 


THE    ANIMAL    PARASITES    OF    MAN 


being  on  the  surface  ;  whereas  the  larva  of  Culex  hangs  head  downwards 
perpendicularly  in  the  water,  the  point  of  the  syphon  only  touching  the  surface. 
In  about  a  fortnight  the  larva  is  fully  grown  and  becomes  a  pupa. 
The  pupa  (fig.  270),  which  carries  out  the  most  remarkable  jerky  movements, 
remains  in  the  water,  but  partakes  of  no  food.  In  shape  it  somewhat 
resembles  a  tadpole,  that  is  to  say,  it  consists  of  a  bulky  anterior  portion 
on  the  surface  of  which  the  head,  with  its  appendages,  is  recognisable,  and 
a  more  slender  segmented  abdomen.  Above,  on  the  thorax,  there  are  two 
small  open  breathing  tubes  for  the  conveyance  of  air  to  the  tracheal 
system.  After  three  or  four  days  the  perfect  mosquito  hatches  out, 
remains  a  short  time  on  the  surface  of  the  water  until  its  chitinous 
integument  is  hardened,  and  then  flies  away.. 


FIG.  270. — Pupa  of  Anopheles  maculipennis,  Meig.   (enlarged).     (After  Grassi.) 


The  females  that  are  fertilised  in  the  autumn  hibernate  in  sheltered 
spots  in  the  open  air,  or  in  houses,  cellars,  under  stairs,  in  stables,  barns, 
&c.,  and  are  the  progenitors  of  the  first  generation  of  the  following  year. 

In  accordance  with  the  climate  of  a  country,  or  the  kind  of  weather 
of  a  year,  the  conditions  in  regard  to  the  manner  of  life  and  the  dura- 
tion of  the  development  of  the  mosquito  varies.  At  all  events,  the  life- 
history  of  the  mosquito  elucidates  many  points  relating  to  malaria  which 
were  hitherto  not  understood. 

[The  length  of  the  egg,  larval  and  pupal,  life  varies  so  much  that  it  is  not 
possible  to  give  an  account  of  any  value  here.  Frequently  the  eggs  may  incu- 
bate in  two  days,  whilst  I  have  had  Stegomyia  fasciata  eggs  from  Cuba  that 
have  hatched  out  under  abnormal  circumstances  more  than  two  months  after 
they  were  laid  ("  Mono.  Culicid.,"  vol.  iii.,  p.  6).  Some  larvae,  as  Anopheles 
bifurcatus,  live  for  months  during  the  winter.  Some  mosquitoes  therefore 
hibernate  as  larvae.  The  larvae  and  pupae  of  the  different  genera  present  very 


OR    MOSQUITOES 


415 


marked  characters,  mainly  in  regard  to  the  structure  of  the  syphons.  Specific 
differences  may  be  found  in  the  frontal  hairs  of  Anopheline  larvae  and  in  the 
number  and  arrangement  of  a  group  of  spines  at  the  base  of  the  syphon  in 
Culicines.— F.  V.  T.] 

LITERATURE. 

FABRIGIUS,  J.  C.     Syst.  antliatorum.     Braunschw.,  1805-06. 

MEIGEN,  J.  W.     Syst.  Beschr.  d.  bek.  europ.  zweifl.  Ins.     7  vols.     Hamm,  1818-38. 

WALKER,  F.     Insecta  Britann.  :    Diptera.     London,  1851-56. 

SCHINER,  J.  R.     Fauna  Austriaca.     Die  Fliegen  (Diptera).     Wien,  1860-64. 

NUTTALL,  G.  H.  F.,  and  A.  E.  SHIPLEY.     Studies  in  Relation  to  Malaria.     Structure 

and  Biology  of  Anopheles  (Journ.  of  Hyg.,  1901,  i.,  p.  451). 
GILES,  G.  M.     A  Handbook   of   the   Gnats  and  Mosquitoes.     2nd  edit.     (Systematic 

part  abridged  from  Theobald).     London,  1902. 
THEOBALD,  F.  V.     A  Monograph  of  the  Culicidae  of  the  World.     3  vols.    London,  1902 

Revision  and  Appendix  of  same,  i  vol.,  1903. 

THEOBALD,  F.  V.     Family  Culicidae,  genera  Insectorium.     Brussels,  1905. 
THEOBALD.  F,   V.     A  Catalogue  of   Culicidae  in  the  National  Museum  of   Hungary. 

Budapest,  1905. 

THEOBALD,  F.  V.     New  Culicidae  from  Ceylon.     Bombay,  1905. 
BLANCHARD,  R.     Les  Moustiques.     Hist.  Nat.  et  Med.    Paris,  1905. 


Q'' 


St. 


FIG.  271. — NEURATION  OF  WING  (Theobald). 

Explanation  of  Wing,  Veins  and  Cells. — A,  Costal  cell;  B,  sub-costal  cell; 
C,  marginal  cell;  D,  first  sub-marginal  cell  (=  first  fork  cell);  E,  second  submarginal 
cell;  F,  first  posterior  cell;  G,  second  posterior  cell  (=  second  fork  cell);  H,  first 
basal  cell;  /,  second  basa.1  cell;  /,  third  posterior  cell;  K,  anal  cell;  L,  auxiliary 
cell;  M,  spurious  cell;  c,  costal  vein;  ist — 6th,  first  to  sixth  longitudinal  veins; 
a,  a  and  a",  incrassations  (a  called  by  Austen  the  sixth  vein,  a"  the  eighth  vein); 
y,  supernumerary  cross  vein ;  z,  mid  cross  vein ;  p,  posterior  cross  vein. 

CULICID.E  OR  MOSQUITOES. 

By  F.    V.  Theobald. 

The  importance  of  these  insects  to  man  is  very  great,  greater  than 
all  the  other  partially  parasitic  animals.  They  not  only  produce  painful 
bites,  which  may  become  inflamed  and  give  rise  to  a  considerable  amount 
of  oedema,  but  they  are  more  important  on  account  of  the  part  they  play 
in  the  distribution  of  various  diseases.  Culicidae  not  only  carry  disease 
germs,  but  act  as  intermediate  hosts  for  certain  parasites,  such  as  some  of  the 
Anophelina  for  malarial  parasites,  Culex  for  Filariae,  and  Stegomyia  for 
yellow  fever ;  the  last-named  is  in  any  case  the  distributor  of  that  fatal 
disease.  It  is  therefore  very  necessary  to  know  the  life-history,  habits  and 
characters  of  these  pests. 

Mosquitoes  exist  in  almost  all  parts  of    the  world  from   the  Arctic  circle 


416 


THE    ANIMAL    PARASITES    OF    MAN 


FIG.  272.— (i)  Heads  of  Culex  and  Anopheles:  (i)  Culex  male;  (2)  Culex  female 
(3)  Anopheles  male  ;  (4)  Anopheles  female.     (After  Daniels.) 


:  OR    MOSQUITOES,  417 

to  trie  tropics  ;  temperate  regions  suffer  from  them  less  than  the  two 
extremes,  but  even  there  they  form  not  only  a  source  of  great  annoyance 
but  of  danger,  as  malaria  and  possibly  now  and  again  yellow  fever  carriers. 
A  few  years  ago  comparatively  few  species  were  known,  now  some  580 
have  been  described.  Their  number  will  probably  not  stop  far  short  of  1,000. 
Some  are  purely  domestic,  others  entirely  sylvan  ;  the  former,  as  we  might 
expect,  often  have  a  very  wide  distribution,  having  been  taken  from  place 
to  place  in  boats  and  trains.  The  more  rapid  transport  becomes,  the  greater 
becomes  the  possibility  of  this  wide  distribution  of  many  species  increasing, 
and  the  spread  of  other  species  from  their  natural  home  to  foreign  parts  by 
sea  and  then  by  trains  further  inland. 

All    Culicidae  'are   aquatic   in    their   larval   and   pupal   stages.      Almost   all 
small  collections  of    water,    both    natural    and    artificial,   may    form    breeding 


FIG.   273. 

a,  Eggs    of  Culex ;    61   b',   Eggs  of  Anopheles;    c,   Egg  of  Stegomyia ;    d,  Egg  of 
Mansonia;    ?,   Egg  of  Psorophora. 

grounds  for  these  pests.  The  favourite  resorts  for  the  larvae  of  Anophelina 
are  small,  natural  collections  of  water,  such  as  puddles,  ditches  and  small 
pools  around  swamps;  certain  species  (A.  maculipennis,  &c.)  live  in  rain 
barrels  as  well.  They  may  also  occur  in  the  sluggish  water  at  the  edges  o 
rivers  or  even  in  mid  river,  where  the  flow  is  checked  by  masses  of  water 
weeds  (Myzomyia  funesta,  &c.).  The  Stegomyias  prefer  artificial  collec- 
tions of  water,  but  also  occur  in  natural  pools.  The  yellow  fever  specie 
(5  fasciata)  prefers  small  collections,  such  as  in  barrels,  pots,  jars,  &c. 
Culex  occur  in  all  manner  of  places-rain  barrels,  tanks,  cisterns,  ponds  and 
ditches  Some  of  the  South  American  species  of  Culex,  Wyeomyia,  Joblotia, 
&c  breed  in  the  collections  of  water  at  the  base  of  Bromelia  leaves.1  Very 
few  Culicid  larvae  live  in  salt  water  except  in  Australia,  where 

•   "  Wald  mosquitoes  und  Wald  malaria,"  Dr.  Lutz.  Ccntnilbt.  /.  Bakt..  &*..  i.  Abt. 
Originate,  Bd.  xxxiii.,  No.  4. 

27 


418 


THE    ANIMAL    PARASITES    OF    MAN 


Bancroft  has  found  them  in  salt  water  of  specific  gravity  10,40  (Afucidus 
alternans,  Culex  anniilirostris  and  C.  marinus,  &c.).  The  food  of  the 
larvae  is  very  varied;  the  majority  appear  to  feed  upon  confervse,  small 


Proboscis 


Antennae 


Palpr 

Eyes""" 
Occiput 

Protboracic" 

lobes 
Mesotborax-- 

Scutellum 
Metathorax""" 

First  abdornfnal 
segment 


Abdomen 


Basa' 
lobes  of  O 


Basal 

lobes —- 74— 

C'asper. £..£ 

Proboscis 

Pcipi 

Antennae 

Basal  lobes  ofantennae 

Fro  no 

Vertex 

Eyes 

Occiput— 
Nape 
FIG.   274. — Diagram  showing  the  structure  of  a  typical  mosquito  (Theobald). 

Crustacea  and  insects  ;  some  are  cannibals,  readily  devouring  others  of  their 
own  kind.  The  larger  larvae  of  Megarhinus,  Psorophora,  Toxorhynchites  and 
Mucidus  are  extremelv  ravenous  and  devour  one  another. 


OR    MOSQUITOES 


419 


There  are  two  main  types  of  larvae,  the  Anopheline  and  Culicine  ;  in  the 
former  there  is  no  respiratory  siphon,  in  the  latter  the  siphon  is  long  or 
moderately  long.  The  head  offers  certain  marked  peculiarities  which  are  of 
specific  value,  this  especially  applies  to  the  Anophelina,  in  which  the  frontal 


tlG.    275. 

Types    of    scales,    a   to  k ;   head  and  scutellar  ornamentation,    I    to  5 ;    forms   of 

clypeus,  6  (Theobald). 

i,  Head  and  scutellum  of  Stegomyia,  &c.  ;  2,  of  Culex  and  Mansonia  ;  3,  of 
Howardina,  JEdes,  &c.  ;  4,  of  Megarhinus  and  Toxorhynchites,  &c.  ;  5,  of  Cellia  and 
some  other  Anophelines  ;  6  a',  clypeus  of  Culcx  :  b',  of  Stegomyia  ;  c  ,  of  Joblotia. 


420  THE   ANIMAL   PARASITES    OF    MAN 

hairs  are  of  great  service  in  distinguishing  the  larvae,1  whilst  in  Culex  the 
number  and  position  of  the  spines  at  the  base  of  and  on  the  siphon  are 
characteristic.  The  position  assumed  by  the  larvae  in  the  water  also  varies 
in  the  different  groups  ;  most  of  the  Anophelines  lie  horizontally,  most  of  the 
Culicina  and  ^Edeomyina  hang  head  downwards.  The  pupae  also  vary,  but 
not  to  the  same  extent;  the  chief  differences  to  be  noticed  are  in  the  form 
of  the  two  respiratory  trumpets. 

The  eggs,  which  may  be  laid  separately  (Anopheles  maculipennis,  Stegomyia 
fasciata,  Joblotia  nivipes,  &c.),  or  in  rafts  (Culex  pipiens,  C.  fatigans\  or 
in  chains  (Tceniorhynchus  fasciolatus\  present  a  great  variety  of  forms.  The 
most  peculiar  are  shown  in  fig.  273  (Mansonia,  Culex,  Stegomyia,  Anopheles}. 

As  in  all  insects  they  differ  very  materially  in  each  species  of  one  genus. 
Those  best  known  are  the  Anopheline  eggs. 

The  eggs  always  float  on  the  surface  of  the  water  ;  immersion  soon 
destroys  them. 

Characters  of  Adult  Culicidce. — The  chief  characters  by  which  true  mosquitoes 
or  CulicidcB  are  known  are  the  following  : — 

(1)  Wings   always   with   the   veins   covered   with   scales  ;     the   longitudinal 
veins  usually  six  in  number  (in  one  genus  seven)  ;     the  costal   vein  carried 
round  the  border  of  the  wing. 

(2)  Head,   thorax  and  abdomen  usually,  but  not  always  (Anopheles,  &c,\ 
covered   with  scales. 

(3)  Mouth  parts   formed  into   a  long  piercing  proboscis. 

As  a  rule  the  males  may  be  told  from  the  females  by  their  antennae 
being  plumose,  whilst  in  the  females  they  are  pilose  (vide  fig.  272',  but  this 
does  not  invariably  hold  good,  for  in  Deinocerites,  Theobald,  and  Sabethes, 
Desvoidy,  and  others,  they  are  pilose  in  both  sexes.  The  labial  palpi  are 
very  variable  in  regard  to  their  form  and  the  number  of  joints  ;  in  the 
Anophelina  they  are  long  in  both  sexes,  as  long  or  nearly  so  as  the 
proboscis,  more  or  less  clubbed  in  the  males  ;  in  Culicina,  Joblotina  and 
Heptaphlebomyia,  they  are  long  in  the  males,  short  in  the  females ;  in 
jEdeomyina,  short  in  both  sexes. 

Scales. — The  most  important  structural  peculiarities  in  CulicidFe  are  the 
scales,  which  form  the  chief  and  most  readily  observed  characters  for 
separating  genera  and  species. 

The  head,  thorax,  abdomen  and  wings  are  in  nearly  all  cases  clothed 
with  squamae  of  varied  form,  of  which  the  following  are  the  main  types 
(fig.  275)  :— 

(1)  Flat,   spade-shaped   scales  (a). 

(2)  Narrow-curved    scales   (e). 

(3)  Hair-like  curved  scales  (d). 

(4)  Spindle-shaped  scales  (/). 

(5)  Small  spindle-shaped  scales  (g). 

(6)  Upright  forked-scales  (h  and  «'). 

(7)  Twisted  upright  scales  (/). 

1  Recent  information  sent  me  by  Dr.  Grabham  shows  this  statement  to  be  not 
quite  correct,  as  the  frcntal  hairs  may  vary  in  different  stages  of  the  same  larva. 
This  he  has  shown  in  Cellia  albipcs,  Theo.,  and  I  have  ncticed  it  in  a  Nyssorhynchus 
from  Africa. 


THE    CLASSIFICATION    OF    CULICID.E 


421 


(8)  Inflated  or  pyriform  scales  (£). 

(9)  Mansonia  scales  (ft). 

(10)  Small  broad  asymmetrical  scales  (c). 

Various  other  varieties  are  found  on  the  wings,  such  as  : — 

(1)  Narrow  linear  lateral  scales. 

(2)  Narrow  lanceolate  scales. 

(3)  Broad  lanceolate  scales. 

(4)  Elongated,  broad,    truncated  scales  (       Tcemorhynchus-like.  scales). 

(5)  Pyriform  scales. 

(6)  Asymmetrical  broad  or  Mansonia  scales. 

(7)  Flat   spade-like   scales.1 

The  wings  have  a  series  of  scales  along  the  middle  line  of  the  veins,  and 
also  lateral  scales  to  all  or  nearly  all  the  veins.  The  wing  is  also  fringed 
by  a  series  of  scales  (fig.  274)  which,  however,  are  of  little  systematic  impor- 
tance ;  the  so-called  "  border-scales  "  (b.s.)  vary,  however,  to  some  extent, 
and  are  useful  characters  in  separating  some  of  the  Mansonias. 


THE  CLASSIFICATION  OF  CULICID^E. 

SECTION  A. — Proboscis  formed  for  piercing  ;   metanotum  nude. 
A.  Palpi  long  in  the  male, 
a  Palpi  long  in  both  sexes. 

First  submarginal  cell  as  long  or  longer 
than  the  second  posterior  cell 

'Wing     scales 
-lanceolate 

Pro  thoracic   Wing    scales 
lobes     sim-      mostly  long 
pie ;  no  flat 
head  scales 


Thorax  and 
abdomen  / 
with  hair-  \ 
like  scales 


and  narrow 
Wing    scales 
partly  large 
and  inflated 

Pro  thoracic  lobes  mammil- 
lated  ;     some    flat     head 
N     scales 

Thorax  with  some  narrow-curved  scales ; 

abdomen  hairy 
Thorax    with    hair-like     curved    scales, 

some    narrow-curved    ones    in    front  ; 

abdomen  with  apical  -lateral  scale  tufts, 

scaly  venter  ;   no  ventral  tuft 
Thorax    with    hair-like    curved    scales  ; 

abdominal  scales  on  venter  only  with 

a  distinct  ventral  apical  tuft 
Much  as  above,  but  abdomen  with  long 

spine-like  dense  lateral  tufts 


Anophelina. 
Anopheles,  Meigen. 

Myzomyia,  Blanchard. 
Cycloleppteron,  Theobald. 

Stethomyia,  Theobald. 
Pyretdphorus ,   Blanchard. 

A  rribalzagia ,  Theobald . 

Myzorhynchus,  Blanchard. 
Chrystia,  Theobald. 


1  Heart-shaped  scales  occur  on  the  wings  of  Etoileptiomyia. 


422 


THE    ANIMAL    PARASITES    OF    MAN 


/Abdominal        scales         as 
j      lateral     dorsal      patches 
of     small     flat     scales  ; 
thoracic     scales     narrow 
and    curved,    or    spindle 
Thorax    and  i     shaped      .  . 

abdomen     Abdomen  nearly  completely 
with  scales       covered     with     irregular 
scales    and   with    lateral 
tufts 

Abdomen  completely  scaled 
with  large  flat  scales,  as 
in  Culex 

First  submarginal  cell  much  smaller  than 
the   second    posterior    cell  ;     proboscis 
long  and  bent    .  .          . .      .•"  ^i: ; 
Palpi  long  in  both  sexes     .  .          .  . 
8  Palpi  short  in  the  female 

First   submarginal   cell  longer   than   the 

second  posterior  cell    ...    . 
Legs  more  or  less   densely  scaly  ;    head 
not  entirely  clothed  with  flat  scales  ; 
all  the  legs  densely  scaly. 
Wings  with  large  pyriform  scales 
Wings  with  narrow  scales 
Hind  legs  only  densely  scaled 
Head  entirely  clothed  with  flat  scales. 
Wing  scales  long  and  rather  thick;  hind 

legs  of  $  with  apical  scaly  paddle 
Legs  uniformly  scaled  with  flat  scales. 
Head   and  scutellar  scales   all   flat    and 

broad. 
Palpi  of  $  short,  of  $  thickened  apically 

and  tufted        JJ, .    ; 

Palpi  of  $  longer  than  in  Stegomyia  and 
in  $  long  and  thin,  acuminate,  simple 
Head  scales  mostly  flat,  but  a  median 
line  of  narrow  curved  ones;  scutellar 
scales  flat  on  mid  lobe,  narrow-curved 
on  lateral  lobes  and  palpi  longer  than 
proboscis 

Head  scales  mostly  flat  irregular,  narrow- 
curved  ones  behind  ;  mid  lobe  scu- 
tellum  with  flat  scales,  lateral  with 
narrow-curved ;  &  palpi  shorter  than 
proboscis. . 

Head  scales  mostly  flat,  but  a  few  narrow- 
curved  ones  in  middle  in  front ;  scu- 
tellar scales  all  flat 

Head  scales  all  flat ;  scutellar  scales  all 
narrow-curved  . 


Nyssorhynchus,  Blanchard. 


Cellia,  Theobald. 


Aldrichia,  Theobald. 


Megarhinina. 

Megarhinus,  Rob.  Desvoidy, 

Toxorhynchites,  Theobald. 

Culicina. 


Mucidus,  Theobald. 
Psorophora,  Rob.  Desvoidy. 
Janthinosoma,  Arribalzaga. 


Eretmapodites,  Theobald. 


Stegomyia,  Theobald. 
Desvoidea,  Blanchard. 


Madeayia,  Theobald. 

Catageiomyia,  Theobald . 

Scutomyia,  Theobald. 
Skusea,  Theobald. 


THE    CLASSIFICATION    OF    CULICIDJ? 


423 


Head    with   flat   scales,    except    a   small 

median  area  of  narrow-curved  ones  ; 

scutellar  scales  all  narrow-curved 
Head  with  all  flat  scales  except  a  thin 

line   of    narrow-curved   ones   behind  ; 

scutellar  scales  all  narrow-curved] 
Head  with  small  flat  scales  over  most  of 

surface,    with    median    line    and    line 

around   eyes  of  narrow-curved   ones  ; 

scutellar  scales  bluntly  spindle  or  club- 
shaped 

Head  and  scutellar  scales  narrow-curved. 
Wing   scales   long,   narrowly  lanceolate, 

collected   in  spots  ;    palpi    clubbed  "in 

$  ;  five-jointed  and  rather  long  in  ?  . . 
Wing   scales   (lateral)  long  and  narrow, 

and     $     palpi     three-jointed,     $     not 

clubbed  and  hairy 
Wing  scales  at  apex  of  veins  dense  and 

rather  broad,    femora   swollen  ;    small 

dark  species 
Wings  with   short,  thick,  median   scales 

and    short,    broadish    lateral   ones    on 

some   of   the   veins  ;     scales    mottled  ; 

fork-cells  rather  short    . .          . . 
Wings  with   dense,   broadish,  elongated, 

truncated  scales 
Wings  with  broad,  short,   asymmetrical 

scales 
Head    covered   with    rather    broad   flat, 

spindle-shaped  scales ;   scutellum  with 

small  flat  scales  to  mid  lobe 
Head  clothed  with   flat,  irregularly  dis- 
posed scales  all  over,  with  patches  of 

narrow-curved  ones  ;    $   palpi  clubbed 
Abdomen    with    projecting    flat     lateral 

scales    with    deeply    dentate     apices  ; 

wings  not  ornamented 
Wings  ornamented  ;  scutellum  with  flat 

and  narrow-curved  scales 
7  Palpi  short  in  $  and  $ 
Wings  unornamented. 
Antennae   pilose  in    $    and    $  ;    second 

joint  very  long 
Antennae  plumose  in  the  $ . 
Head    clothed  with  narrow-curved    and 

flat  scales. 
Mid  lobe  of  scutellum  with  six  borde  - 

bristles. 

Scutellum  with  narrow-curved  scales. 
Palpi  in  $  four-jointed,  in  $  two-jointed 


Howardina,  Theobald. 
Daniel sia,  Theobald. 

.Hulecoetomyia,  Theobald 

Theobaldinella,  Blanchard. 

Culex,  Linnaeus. 

M elanoconion ,  Theobald. 

Grabhamia,  Theobald, 
Tczniorhynchus,  Arribalzaga. 
Mansowia,  Blanchard. 

Gilesia,  Theobald. 
Acartomyia,  Theobald. 

Lasioconops,  Theobald. 

Finlaya,  Theobald. 
JEdeomyina. 

Deinocerites,  Theobald. 


,  Meigen. 


424 


THE    ANIMAL    PARASITES    OF    MAN 


Mid  lobe  of  scutellum  with  four  border- 
bristles. 
Scutellum  with  flat  scales. .          ..          .. 

Head  clothed  with  flat  scales  only. 
Fork-cells  normal  length. 
Mid  lobe  of  scutellum  with  four  border- 
bristles^ 

Palpi  of  ?  two-jointed 
Palpi  of  $  five-jointed,  metallic 
Fork-cells  very  small  or  small.  ;> 
Scutellar  scales  flat. 
First   sub-marginal   cell  longer  than  the 

second   posterior  cell ;    no  flat    scales 

on  mesothorax 
First  sub-marginal  cell  smaller  than  the 

second    posterior  cell;    flat   scales    on 

mesothorax 

.   Scutellar  scales  narrow-curved. 
First  sub-marginal  cell  as  in  Uranottenia 
Wings   ornamented   with    Mansonia-like 

scales  i^. . . 
SECTION^B. — Metanotum      ornamented      with 

chaetae,  squamae  or  both, 
a  With  chaetae  only. 

Proboscis  longer  than  whole  body  ;  lateral 
M,  Sowing  scales  T&niorhynchus-like 

Proboscis  as  long  as  whole  body  in   $  ;") 

frons  drawn  out  into   a    prominence  ;  j. 

wing  scales  rather  broad  and  long       .  .  ) 
Proboscis    not    as    long    as    the    whole 

body  ;  lateral  vein- scales  narrow 
Proboscis    not    as  long   as   whole  body, 

swollen     apically  ;     wing    scales    long 

and  broad 

$  Metanotum  with  squamae  and  chaetae. 
Palpi  short  in  $  and   $  . 
Proboscis  straight  in  ?  and  $  ;  legs  with 

scaly  paddles 
Venation  like  Sabethes. 
Legs  simple 
Venation  like  Culex 
Proboscis  in  $  elbowed,  with  two  scaly 

tufts 

Palpi  long  in  $  ,  short  in  ? 
II.  Wings    with    seven    scaled    longitudinal 

veins  ;  Culex  type 
SECTION  C. — Proboscis    short,   not   formed   for 

piercing 

Metatarsus  longer  than  first  tarsal  joint. . 
Metatarsus     shorter     than    first     tarsal 

joint         . . 


JEdimorphus ,  Theobald. 


Verallina,  Theobald. 
HcBmagogus,  Williston. 


Ficalbia,  Theobald. 

Uranotcenia,  Arribalzaga. 
Mimomyia,  Theobald. 
ffidiomyia,  Theobald. 


Phoniomyia,  Theobald. 

Binotia,  Blanchard  = 
Runchiomyia,  Theobald. 


Wyeomyia,  Theobald. 


Dendriomyia,   Theobald. 


Sabethes,  Rob.  Desvoidyl 

Sabethoides,  Theobald. 
Goeldia,  Theobald. 

Limatus,  Theobald. 
Joblotina,  Blanchard, 

Heptaphlebomyia ,  Theobald. 

Corethrina. 
Corethra,  Linnaeus. 

Mochlonyx,   Ruthe.  l 


1  Since  this  went  to  press  many  new  genera  have  been  created  ;  these  will  be  found 
in  my  catalogue  of  Culicidae  in  the  Nat.  Mus,  Hongrois,  in  Family  Culicidae,  genera 
Insectorum,  and  in  New  Culicidae  from  Ceylon. 


NOTES  ON  THE  DIFFERENT  GENERA  425 

NOTES  ON  THE  DIFFERENT  GENERA. 

Sub-family  A  nophelina . 
Genus  i.     Anopheles,  Meigen. 

\Syst.  Beschr.  Europ.  Zwei.  Ins.  /.,  ii.,  2  (1818).  Meigen;  Mono.  Culicid., 
i.,p.  191,  andiii.,  p.  17,  1903. — Theob.] 

This  genus  contains  a  few  large  species  found  either  in  temperate 
climates  or  in  hills  and  mountains  of  warm  climates.  The  type  is  the 
European  and  North  American  A.  maculipennis. 


FJG.   276. — WING  OF  Anopheles  maculipennis,  Meigen. 

Anopheles  maculipennis }  Meigen.  This  species  and  A.  bifurcatus  are 
malaria  carriers.  True  Anopheles  only  occur  in  Europe,  North  America, 
the  North  of  Africa  and  in  the  Mountains  of  India,  and  one  has  recently 
been  found  by  Bancroft  similar  to  A.  bifurcatus  in  Queensland.  They  are 
easily  told  by  the  absence  of  scales  on  thorax  and  abdomen,  and  by  the 
rather  densely  scaled  wings  with  lanceolate  scales. 


Genus  2.     Myzomyia,  Blanchard  ;   Grassia,  Theobald. 

[Comp.  Rend.  Heb.  Soc.  Biolog.,l$o.  23,  p.  795  (Blanchard)  ;  Mono.  Culicid. 
iii.,  p.  24. — Theob.] 

This  genus  occurs  in  Asia,  Africa  and  South  America,  Europe  and  East 
Indies.  The  type  is  M.  funesta,  Giles,  found  in  Central  and  West  Africa. 
Some  fifteen  species  occur  in  this  genus.  Although  structurally  there  is 
not  much  difference  between  this  genus  and  Anopheles,  they  differ  greatly 
in  appearance,  and  there  are  usually  a  few  narrow-curved  thoracic  scales 
projecting  over  the  head,  whilst  the  wing  scales  are  much  smaller  in  pro-, 
portion,  and  the  wings  more  uniformly  spotted,  always  so  along  the  costa. 
Funesta  is  undoubtedly  a  malaria  bearer. 


Genus  3.     Cycloleppteron,  Theobald. 

Mono.  Culicid.,  ii.,  p.  312,  1903. 

Two  species  only  occur  in  this  genus,  C.  grabhamii,  Theob.,  from  Jamaica, 
and  C.  mediopunctatus ,  Theob.  (Lutz.,  ms.\  from  South  America.  The  chief 
character  is  the  presence  of  large  black  inflated  pyriform  scales  on  the 
wings.  The  palpi  are  densely  scaled.  Neither  have  been  shown  to  be 
malaria  bearers. 


426  THE   ANIMAL   PARASITES    OF   MAN 

Genus  4.     Stethomyia,  Theob. 

Mono.  Culicid.,  iii.,  p.  13,  1903. 

Two  species  occur  in  the  marked  genus — one  5.  nimba,  Theob.,  from 
British  Guiana  and  Para,  another  5.  fragilis,  Theob. ,  from  the  Malay  States. 

The  former  may  be  a  malarial  carrier,  for  Dr.  Low  says,  "  Malarial 
fever  is  got  amongst  the  Indians  and  often  of  a  severe  type.  In  that  con- 
nection it  is  interesting  that  in  the  interior,  at  a  place  called  Corato,  I  got 
an  entirely  new  Anopheles  in  large  numbers."  The  genus  is  easily  told  by 
its  unornamented  wings,  flat  head  scales,  mammillated  prothoracic  lobes 
and  long  thin  legs. 

Genus  5.     Pyretophorus,  Blanchard  ;    Howardia,  Theobald. 

Compt.  Rend.  Hebdotn.  Soc.  d.  Biolog.,  23,  p.  795  ;  Blanchard,  Journ.  Trap. 
Med.y  v.,  181,  and  Mono.  Culicid.,  iii.,  13,  1903,  Theobald. 

Ten  species  come  in  this  genus,  of  which  Anopheles  costalis,  Loew,  is  the 
type. 

This  genus  is  found  in  Africa,  India,  Europe  and  in  Australia.  Two 
species  are  proved  malaria  bearers,  namely,  P.  costalis,  Loew,  and  P.  chau- 
doyei,  Theob.  Members  of  this  genus  can  be  told  by  having  narrow-curved 
thoracic  scales,  hairy  abdomen,  and  much  spotted  wings. 

Genus  6.     Arribalzagia,  Theobald. 

Mono.  Culicid.,  iii.,  pp.  13   and  81,   1903. 

A  single  species  only  occurs,  found  in  South  America.  The  thorax  and 
abdomen  have  scales  and  hairs  respectively,  as  in  Pyretophorus,  but  the 
abdomen  has  in  addition  prominent  lateral  apical  scale  tufts  to  the  segments 
and  a  scaly  venter.  Wings  with  membrane  tinged  in  patches  and  wing 
scales  bluntly  lanceolate  and  very  dense.  The  type  is  A.  maculipes, 
Theobald. 

Genus  7.     Myzorhynchus,  Blanchard  ;    Rossia,  Theobald. 

Comp.  Rend.  Heb.  Soc.  Biologie,  No.  23,  p.  795,  1902  ;  Blanchard, 
Journ.  Trop.  Med.,  p.  181,  1902,  Theobald. 

A  very  marked  genus  of  large  dark,  densely  scaled  species,  found  in 
Europe,  Asia,  Africa  and  Australia.  The  thorax  with  hair-like  curved 
scales  ;  the  abdomen  with  ventral  and  apical  scales,  and  a  median  ventral 
apical  tuft,  and  with  very  densely  scaled  palpi  in  the  ? ,  and  densely 
scaled  proboscis.  It  seems  to  be  mainly  an  Asiatic  and  East  Indian  genus, 
but  three  species  occur  in  Africa  and  one  in  Australia.  They  are  mostly 
sylvan  species  and  bite  severely. 

Genus  8.     Nyssorhynchus,  Blanchard  ;    Laverania,  Theobald. 

Mono.  Culicid.,  iii.,  p.  14,  Theobald  ;  Compt.  Rend.  Hebd.  Soc.  Biologie ,  No. 
23,  p.  795,  Blanchard. 

A  group  of  small,  closely  allied  species  found  in  India,  Africa  and  Australia. 
It  appears  to  be  essentially  an  Indian  genus — seven  out  of  the  twelve 


NOTES    ON    THE    DIFFERENT    GENERA  427 

species  coming  from  India  and  another  (maculipalpis,  Giles)  is  apparently 
common  to  India  and  Africa. 

The  thorax  is  covered  with  narrow-curved  and  spindle-shaped  scales, 
abdomen  with  small,  flat  or  narrow-curved  dorsal  scales,  especially  on  the 
apical  segments  or  in  patches  ;  the  legs  are  always  banded  or  spotted  with 
white,  and  the  tarsi  have  as  a  rule  one  or  more  pure  white  segments.  (This 
banding  and  spotting  is  of  no  generic  value,  however.) 

The  species  show  considerable  seasonal  variation.  The  type  of  the 
genus  is  N.  maculatus,  Theobald. 

Genus  9.     Cellia,  Theobald. 

Mono.  Culicid.,  iii.,  p.  14.         • 

Very  marked  Anophelines,  with  densely  scaly  abdomens,  the  scales 
irregularly  disposed  on  the  dorsum  and  forming  dense  lateral  tufts  ;  thorax 
with  flat  spindle-shaped  scales,;  palpi  densely  scaled  and  also  the  wings. 

The  type  of  the  genus  is  the  African  C.  pharoensis,  Theob.  It  is  repre- 
sented in  Asia  by  C.  kochii,  Donitz  ;  in  West  Indies  and  South  America  by 
C.  argyrotarsis,  Desvoidy,  and  C.  bigotii,  Theob.,  in  Africa  by  C.  squamosa, 
Theob.,  &c. 

C.  argyrotarsis,  Desvoidy,  and  C.  alpibes,  Theobald,  are  undoubtedly 
malaria  bearers,  also  C.  pharoensis. 

Genus  10.     Aldrichia,  Theobald. 

Mono.  Culicid.,  hi.,  p.  353,  1903. 

A  single  species  only  occurs,  represented  by  one  specimen  in  the  British 
Museum.-1  The  abdomen  is  completely  covered  with  large,  flat  over-lapping 
scales,  as  in  Culex  ;  the  thorax  with  very  narrow-curved  scales,  almost  hair- 
like,  and  the  prothoracic  lobes  with  outstanding  flat  scales.  The  single 
species,  Aldrichia  error,  Theob.,  was  taken  in  India  and  placed  by  Giles 
amongst  his  types  !  of  rossii 

Sub-family  Megarhinina. 
Genus  n.     Megarhinus,  Robineau-Desvoidy. 

All  large  brilliant  mosquitoes  with  long  palpi  in  both  sexes  and,  as  a 
rule,  with  a  caudal  fan  of  scales  ;  the  proboscis  is  long  and  bent.  They 
are  all  sylvan  species,  and  are  not  so  far  recorded  as  biting  man. 

Genus  12.     Toxorhynchites,  Theobald. 

Mono.  Culicid.,  i.,  p.  244,  1901. 

Differs  from  the  former  genus  in  that  the    ?    palpi  are  short. 
The    Elephant    mosquito  of    India   (Toxorhynchites   immiseticors),  Walker, 
bites  very  severely.      They  are  sylvan  species. 

Sub-family  Culicina. 
Genus  Mucidus,  Theobald. 

Mono.  Culicid.,  i.,  p.  268,  1901. 

This  genus  is  so  far  confined  to  Australia,  West,  and  Central  Africa, 
East  Indies  and  Malay  Peninsula.  They  are  all  large  mosquitoes,  easily 

1  Others  have  since  occurred. 


428  THE    ANIMAL    PARASITES    OF    MAN 

told  by  the  whole  body  being  more  or  less  covered  with  long  twisted  scales, 
giving  them  a  mouldy  appearance,  and  the  legs  densely  scaled  with  out- 
standing scales  ;  the  wings  with  large  parti-coloured  scales.  The  Australian 
M.  alternans,  Walker,  occurs  in  larval  forms  both  in  fresh  and  salt  water. 
The  adults  bite  man. 

Genus  Psorophora,  Robineau-Desvoidy. 

This  genus  is  confined  to  the  Americas  and  the  West  Indies.  Four 
species  exist  which  can  easily  be  told  from  Mucidus  by  the  absence  of  long 
twisted  scales  and  the  narrower  wing  scales.  The  legs  are  densely  scaled 
and  the  thorax  ornamented  with  flat  spindle-shaped  scales. 

Psorophora  ciliata,  Robineau-Desvoidy,  occurs  in  both  North  and  South 
America,  and  bites  man. 

Genus  Janthinosoma,  Arribalzaga. 

Hind  legs  only  densely  scaled  ;  some  of  the  hind  tarsi  are  always  white. 
The  venation  is  as  in  Culex.  The  abdomen  is  metallic  and  iridescent. 
They  all  bite  man  and  occur  only  in  the  Americas  and  West  Indies. 

Genus  Stegomyia,  Theobald. 

After  Anopheles  this  is  the  next  most  important  genus,  on  account  of  the 
connection  of  5.  fasciata  with  yellow  fever.  This  genus  is  easily  told  by 
the  head  and  scutellum  being  entirely  clothed  with  flat  scales.  They  are 
mostly  black  and  white  mosquitoes,  and  are  known  in  India  as  tiger  mos- 
quitoes. The  best  known  species  is  S.  FASCIATA  ;  it  is  found  in  all  parts  of 
the  world  between  40°  N.  and  S.  It  is  a  most  vicious  biter  both  by  day 
and  night,  and  breeds  in  small  artificial  collections  of  water,  such  as  barrels, 
puddles,  cisterns,  and  even  in  such  small  receptacles  as  sardine  tins.  The 
character  by  which  this  species  is  told  is  the  ornamentation  on  the  thorax, 
which  has  a  curved  silvery  line  on  each  side  and  two  dull  yellow  parallel  ones 
in  the  middle  ;  but  it  is  subject  to  much  variation,  some  specimens  (variety 
mosquito}  having  no  median  thoracic  stripes. 

Stegomyia  scutellaris,  Walker. 

A  vicious  biter,  found  in  India,  China,  Malay,  and  East  Indies,  Fiji  and 
Ceylon.  The  thorax  has  one  median  silvery  stripe,  and  so  can  easily  be 
told  from  5.  fasciata.  ^ 

A  number  of  nearly  allied  genera  occur  here  (vide  synoptic  table). 

Genus  Theobaldinella,  B\o.i\ch3ird==Theobaldia,  Neveu-Lemaire. 

.     Includes    several    large    Culicines,    of    which    T.    annulata,    Meigen,    is    the 
type       The    wings   are    usually   spotted    (annulata,    incident,    &c.),    but    may 
be  nearly  plain  (spathipalpis\      The   $   have  the  palpi  swollen  apically,   and 
the    $    have  long  five- join  ted  palps. 
Several  of  these  are  vicious  biters. 


NOTES    ON    THE    DIFFERENT  GENERA  429 

Theobaldinella  annulata,  Meigen. 

This  large  gnat  (6  mm.  long)  can  be  told  by  its  wings  having  five  large 
spots  of  dark  scales  and  by  its  legs  having  broad  basal  white  bands  to 
the  tarsi.  The  larvae  occur  in  rain  barrels  and  small  pools.  It  is  essen- 
tially a  domestic  form,  occurring  in  houses  and  privies.  Its  distribution  is 
Europe  generally  and  North  America.  The  bite  is  very  severe,  and  in  some 
districts  gives  rise  to  painful  oedema.1 

Theobaldia  spothipalpis,  Rondani,  occurs  in  Italy,  Mediterranean  Islands, 
Palestine,  the  Himalayas,  Khartoum,  and  in  South  Africa.  It  is  about  the 
same  size  as  T.  annulata,  but  is  yellowish-brown  in  colour,  with  striped- thorax 
and  mottled  and  banded  legs.  It  occurs  in  privies  and  bites  very  severely. 

Genus  Culex,  Linnaeus. 

This  large  genus  still  contains  many  forms  which  should  be  excluded. 
The  species  normally  have  narrow-curved  median  head-scales,  and  similar 


FIG.  277. — WING  OF  A  Culex. 

ones  on  the  scutellum  ;  the  $  palpi  are  shorter  than  in  the  former  genus 
and  the  male  palpi  are  pointed  ;  the  lateral  vein-scales  are  narrow  and  linear. 

The  type  is  Culex  pipiens,  Linn.,  the  common  gnat  of  Europe.  The 
thorax  is  covered  with  narrow-curved  golden-brown  scales,  the  abdomen 
has  basal  pale  bands  to  the  segments  and  the  legs  and  proboscis  are 
unbanded.  The  stem  of  the  first  submarginal  cell  is  always  less  than  one- 
fifth  the  length  of  the  cell.  It  lays  its  eggs  in  rafts,  in  water  butts,  &c., 
and  even  in  the  foulest  water.  They  are  first  deposited  in  England  in 
June  and  July  and  again  soon  after  hatching  in  August.  In  some  districts 
this  gnat  bites  man  viciously,  in  others  not  at  all. 

The  common  tropical  gnat  (Culex  fatigans,  Wied).  This  resembles  the 
European  Culex  pipiens,  but  can  always  be  told  by  the  stem  of  the  first 
submarginal  cell  always  being  much  longer  than  it  is  in  C.  pipiens.  This 
is  one  of  the  species  that  has  been  proved  to  transmit  Filariae  to  man,  &c. 
Varieties  of  it  occur  in  almost  every  country  between  40°  N.  and  S.,  having 
a  very  similar  range  to  5.  fasciaia.  In  all  countries  it  appears  to  be  con- 
nected with  the  transmission  of  Filariasis, 

Genus  Melanoconion,  Theobald. 

Mono.  Culicid.,  iii.,  p.  238,   1903. 

This  genus  is  composed  of  eight  species,  most  of  which  are  small  black  gnats 
which  bite  viciously  and  which  occur  in  swamps  and  jungles.  They  can  at 
once  be  told  from  Culex  by  the  veins  of  the  wings  having  dense  broadened 

1  Second  Report  on  Economic  Zoology,  p.  9,  1903.     Theobald. 


430  THE    ANIMAL    PARASITES    OF    MAN 

scales  on  their  apical  areas  and  along  the  upper  costal  border.  The  femora 
and  apices  of  the  tibiae  are  swollen. 

The  black  mosquito,  Melanoconion  atratus,  Theob.  This  small  gnat  is  a 
very  troublesome  pest  in  swamps  in  the  West  Indies.  The  female  bites  both 
by  day  and  by  night,  and  the  bite  causes  severe  irritation.  The  larvae  live 
in  permanent  ponds.  It  is  almost  black  in  colour,  but  sometimes  presents 
a  dull  coppery-sheen  ;  each  segment  has  small  lateral  basal  white  spots. 
Length  2*5  to  3  mm. 

It  occurs  in  Para  and  British  Guiana  as  well   as  in   the  West  Indies. 

Ordinary  mosquito  netting  is  no  use  for  keeping  off   this  pest. 


Genus  Grabhamia,  Theobald. 

Mono.  Culicid.,  iii.,  p.  243,   1903. 

Allied  to  Culex,  but  separated  by  the  wings  having  short  fork-cells, 
mottled  scales,  the  median  ones  thick  and  also  some  of  the  lateral  ones 
short  and  broad  ;  the  last  two  joints  of  the  male  palps  are  very  slightly 
swollen.  The  eggs  are  laid  singly,  not  in  rafts,  and  the  larvae  have  short, 
thick  siphons.  Ten  species  occur  and  are  found  in  Europe,  N.  America,  West 
Indies  and  Natal.  G.  dorsalis,  Meigen,  bites  severely  in  Europe.  G.  sollicitans, 
Walker,  is  a  great  scourge  along  the  New  Jersey  Coast  and  at  Virginia 
summer  resorts  and  in  Florida.  It  breeds  in  brackish  water,  and  is  the  most 
common  mosquito  of  the  Atlantic  seaboard. 


Genus  T&morkynchits,  Arribalzaga. 

Differs  from  the  former  in  having  the  whole  wing  veins  clothed  with  dense, 
broadish  elongated  scales.  They  occur  in  South  America  (T.  fasciolatus,  Arri.  ; 
T.  fulvus,  Wied.) ;  in  Africa  (T.  tenax,  Theob.)  ;  in  Asia  (T.  conopas,  Frau  ; 
T.  aurites,  Theob.,  &c.),  in  Europe  (^.  richardii,  Ficalbi). 

A  yellowish  species,  T.  fuscopennatus,  Theob.,  with  black  apices  to  some 
of  the  tarsi,  occurs  in  Uganda,  both  in  the  forest  and  indoors  in  great 
numbers.  Dr.  Loew  found  filariae  in  the  thoracic  muscles  of  this  species. 


Genus  Mansonia,  Blanch ard  ;    Panoplites,  Theobald. 

Compt.  Rend.  Hebd.  Soc.  d.  Biol.,  37,  iii.,  p.  1046,  1901  ;  Mono.  Culicid. ,  ii., 
p.  173,  1901. 

A  very  marked  genus  easily  told  by  the  broad  asymmetrical  wing  scales. 
It  occurs  in  Africa  (M .  uniformis  and  M.  major,  Theob.)  ;  in  Asia  (M. 
uniformis,  Theob.  ;  M.  annulipes,  Walker,  &c.)  ;  and  in  Australia  (M.  austra- 
tiencis}  ;  in  the  Americas  and  West  Indies  (M.  titillans,  Walker).  The  eggs 
(fig.  273,  d}  are  peculiar  in  form  and  are  laid  separately  ;  the  larva  has  not 
been  described  ;  the  pupa  has  long  curved  siphons.  They  mostly  occur  along 
rivers,  in  swamps  and  forests,  and  bite  very  severely.  They  also  enter  houses 
(M.  titillans}.  M.  uniformis  is  most  troublesome  during  the  rains.  The 
saliva  is  strongly  acid. 


OTHER    NEMATOCERA  43! 

Genus  Acartomyia,  Theob. 

Mono.  Culicid.,  iii.,  p.  251,   1903. 

A  single  species,  A.  zammtii,  Theob.,  only  known,  which  occurs  in  large 
numbers,  breeding  in  salt  pans  along  the  shore  line  in  Malta.  It  bites 
severely. 

The  genus  differs  from  Grabhamia,  to  which  it  is  nearest  related,  by 
having  irregular  flat  scales  over  the  head,  not  closely  applied  as  in  Stegomyia, 
but  loose  and  irregular.  It  is  possible  that  there  is  a  connection  between 
this  species  and  Mediterranean  fever. 

Several  of  the  ^deomyina  bite,  especially  the  small  Uranotcenias.  They 
are  all  sylvan  species,  seldom  entering  houses.  They  need  not  therefore 
be  referred  to  here. 

For  full  details  of  the  Culicid  genera  and  species  the  reader  is  referred 
to  my  Monograph,1  and  my  recent  work  in  genera  Insectorum  (1905). 


Other  NEMATOCERA. 

Other  Nematocerous  flies  are  midges,  daddy-long-legs  and  sand-flies.  The 
ones  which  cause  annoyance  to  man  besides  Culicidce  are  the  following  : — 

Sand-flies,  Simulida  ;  certain  Midges,  Chironomtdce,  and  a  few  Owl  midges, 
PsychodidcB. 

The  Nematocera  have  long  thread-like  jointed  antennae  and.  their  pupae 
are,  as  a  rule,  naked  ;  the  larvae  have  a  distinct  head  and  can  thus  be 
told  from  the  next  section  (Brachycera). 


Sand-flies  or  Sinmlidce. 

[These  flies  are  also  known  as  black  flies,  buffalo  gnats,  and  sometimes 
are  wrongly  called  mosquitoes.  One  genus  only  exists,  viz.,  Simulium. 
They  occur  from  Iceland  to  the  Tropics  and  often  swarm  in  damp  places. 
Their  bite  is  very  severe  and  produces  intense  pain  both  in  animals  and 
man.  They  are  all  dark  coloured,  small  flies,  stoutly  built,  with  largish 
wings  ;  the  first,  second  and  third  veins  dark,  the  rest  pale  ;  legs  stout 
and  compressed,  unarmed. 

The  larvae  are  aquatic  and  hold  on  to  stones,  grass  and  water  weeds, 
twigs  and  roots.  When  young  they  are  transparent,  usually  later  becoming 
grey  or  brt>wn  ;  they  prefer  running  water  to  still,  attaching  themselves  by 
a  number  of  hooklets  on  the  posterior  part  of  the  body  ;  they  thus  hang 
head  downwards  and  collect  food  by  the  aid  of  a  pair  of  fan-like  scoops 
upon  either  side  of  the  head  ;  on  the  ventral  surface  of  the  thorax  is  a 
kind  of  proleg  used  for  movement,  the  larva  progressing  much  after  the 
manner  of  a  "  canker-worm  "  or  "  looper-larva."  They  have  also  the  power 
of  forming  a  silken  cord,  with  the  aid  of  which  they  drop  slowly  down 
the  stream  until  a  fresh  foothold  is  secured. 

The  pupal  stage  is  passed  in  a  small  shoe-shaped  cocoon  open  at  one  end, 

1  "  A  Monograph  of  the  Culicidse  of  the  World,"  2  vols.  and  atlas,  1901.  and  vol.  3 
and  plates,  1903.  British  Museum  (Nat.  Hist.). 


432  THE    ANIMAL    PARASITES    OF   MAN 

which  is  formed  by  the  larva  of  a  silky  substance.  The  pupa  enclosed  in 
this  brown  cocoon  is  bright  brown  with  crimson  eye  spots  (in  some  species)  ; 
on  the  front  of  the  pupa  are  four-branched  respiratory  filaments  on  either 
side  ;  these  and  the  head  of  the  pupa  project  from  the  cocoon.  The  flies 
are  most  restless,  and  even  when  stationary  continually  move  their  legs 
about,  moving  them  like  feelers.  They  are  gregarious,. 

Simulium  columbaschensis  is  a  great  plague  to  man  and  beasts  in  parts 
of  Hungary,  &c  It  is  known  as  the  "  Kolumbatz  fly."  It  derives  its 
name  from  an  old  Servian  castle  in  the  district  of  Poshararatz,  where  it 
abounds  in  damp  marshy  lands  along  the  Danube.  It  is  abundant  in 
Austria  and  Moravia  as  well,  and  is-  most  numerous  after  inundations  from 
the  Danube.  They  sometimes  appear  in  such  swarms  that  it  is  impossible 
to  breathe  without  getting  them  into  one's  mouth,  and  white  animals 
become  quite  black.  There  are  instances  of  children  being  killed-  by  these 
flies,  which  swarm  over  them  when  left  by  their  mothers  on  the  ground 
when  they  are  occupied  in  the  fields. 

Simulium  maculatum,  Meigen. 

Female  bluish-grey  with  three  black  stripes  on  the  thorax  ;  abdomen 
with,  three  black  spots  above;  male  dusky  black  with  the  sides  of  the 


FIG.   278. — WING  OF  Simulium.  FIG.   279. — WING  OF  Chironomus. 

thorax  yellowish  in  front  and  the  base  of  the  abdomen  yellow  on  each 
side.  Length  2  to  2-5  mm. 

This  so-called  spotted  Simulium  now  and  again  attacks  man  in  Europe, 
but  especially  horses  and  cattle. 

Other  species,  as  5.  reptans,  Linn.,  and  5.  cinerum,  Mac.,  are  very 
annoying  to  man  in  Great  Britain  and  Europe,  biting  very  fiercely  and 
causing  painful  wounds 

S.  reptans*  is  2  to  3  mm.  long  ;  the  female  is  grey,  the  male  dark  and 
velvety  with  grey  sides  to  the  thorax  ;  base  of  wings  and  balancers  yellow 
and  legs  with  white  rings. 

S.  cinerum,'  Mac.,  is  dark  grey  with  three  dark  thoracic  lines  and  three 
dark  lines  on  the  thorax  ;  antennae  and  legs  black.  Length  3  to  3-5  mm. 

5.  damnosum,  Theob./  a  small  sand  fly,  known  as  the  "  Jinja  Fly,"  is  found 
forming  a  "  fly  belt  "  from  the  shores  of  Victoria  Nyanza  northwards  along  the 
right  bank  of  the  Nile,  for  twelve  or  fifteen  miles  or  more,  and  about  three  to 
four  miles  wide.  At  certain  seasons  it  swarms  in  such  numbers  and  is  such 


1   "  An  Account  of  British  Flies,"  vol.  i.,  p.  167.     Theobald. 
'*  Proc.  Royal  Soc.,  "Sleeping  Sickness  Report,"  ii..  1903. 


CHIRONOMID^E 


433 


a  plague  that  the  natives  leave  their  plantations.  On  nearing  the  sphere  of 
influence  of  the  Jinja  fly  the  porters  stop  and  break  off  branches  to  use  as  fly 
swishes,  then  collect  together  and  travel  at  an  increased  speed.  The  fly  is 
3  mm.  long,  of  a  general  black  colour,  with  bright  deep  golden  hairs  on  the 
thorax,  and  the  metatarsi  of  the  hind  legs  with  a  median  pale  yellow  band. 

Numerous  other  undescribed  species  have  been  sent  me  from  the  Tropics, 
where  they  are  known  under  a  variety  of  names,  such  as  black-fly,  brulots, 
sand-flies,  &c. 

Family  Chironomidce. 

The  Chironomidae  or  midges  are  not  only  frequently  mistaken  for 
mosquitoes,  but  some  are  undoubtedly  very  annoying  to  man  by  biting 
him  as  mosquitoes  do.  They  are  easily  distinguished  from  true  mosquitoes 
(Culicidai)  by  the  following  characters  :  (i)  head  small,  often  retracted  under 
the  cowl-like  thorax  ;  (2)  no  scales  to  the  wings  or  body  and  (3)  the 
different  arrangement  of  veins  on  the  wings  (fig.  275). 

One  genus  only  is  important  as  annoying  man,  namely,  Ceratopogon. 
The  larvae  are  either  aquatic,  both  fresh  water  and  marine,  and  help  to 


FIG.  276. — A  Ceratopogon  or  Midge  (greatly  enlarged). 

make  the  former  foul1  according  to  Slater,  or  may  as  in  Ceratopogon  live 
beneath  the  bark  of  'trees.  The  pupae  are  very  varied  and  also  the  life- 
histories  of  the  different  genera.2 


Genus  Ceratopogon. 


Body  small,  pilose  or  bare  ;  head  produced  into  a  short  rostrum  ; 
proboscis  with  fleshy  labium,  labrum  horny  ;  maxillae  long  and  horny ; 
wings  mostly  mottled  .  The  thorax  is  not  produced  as  a  cowl  over  the 
head.  Abdomen  composed  of  eight  segments,  hairy.  The  larvae  are 


1   "  Entomologist,"  p.  89,  1879. 

-  "  An  Account  of  British  Flies,"  vol.  i.,  Theobald,  p.   172. 

28 


434  THE    ANIMAL    PARASITES    OF    MAN 

terrestrial  and  often  dwell  beneath  the  bark  of  decaying  trees  and  even  in 
manure.  They  are  cylindrical  white  grubs  with  the  anterior  part  slightly 
enlarged  ;  head  small  and  retractile,  segments  deeply  constricted,  with 
appendages  on  the  pro  thorax  and  on  the  anal  segment.  The  pupae  are 
much  shorter  than  the  larvae  and  are  broadest  in  front  with  two  short  lateral 
appendages  ;  some  have  long  filiform  appendages  on  the  back  of  the  thorax. 
This  group  of  midges  are  known  in  America  as  "  punkies."  They  are 
most  troublesome  in  the  Tropics,  but  cause  great  annoyance  by  their  bites 
in  many  countries  with  temperate  climates.  Little  or  nothing  is  known  of 
the  exotic  species. 

Psychodidce,  or  Owl  Midges. 

These  small  flies  are  easily  told  by  their  extremely  hairy  wings  and 
bodies  and  general  moth-like  appearance.  The  proboscis  is  usually  short, 
but  in  some  exotic  genera  (Phlebotomus ,  &c.),  it  is  elongated  and  horny,  and 


FIG.   277. — An  Owl  Midge,  Phlebotomus,  sp.,  greatly  enlarged. 
(From  Giles'  "  Gnats  or  Mosquitoes.") 

these  are  vicious  blood  suckers.  The  larvae  live  in  water,  in  rotting 
vegetable  substances ;  they  are  more  or  less  cylindrical  with  a  short  ter- 
minal stigmatic  tube.  The  pupae  have .  two  long  tube-like  anterior  stigmata. 
The  genus  Phlebotomus  occurs  widely  over  tropical  climes  ;  specimens 
have  been  received  by  me  from  India,  West  and  Central  Africa  and  South 
America.  They  frequently  occur  on  windows  in  houses. — F.  V.  T.] 

(b)  Brachycera  (Flies). 

The  antennae  as  a  rule  have  three  joints,  and  are  usually  shorter  than 
the  head.  The  first  joint  of  the  antennae  is  frequently  very  small,  and 
the  third  one  is  generally  the  largest,  and  sometimes  possesses  a  terminal 
annulated  bristle.  The  palpi  have  from  one  to  three  joints;  the  mandibles 
are  covered  by  the  labium.  The  three  thoracic  rings  are  coalesced  ; 
wings  are  almost  always  present,  the  posterior  ones  being  rudimentary  and 
covered  with  a  little  scale.  From  the  ova  legless  maggots  are  hatched, 
which  as  a  rule  have  not  a  distinct  head,  but  occasionally  possess  two 


BRACHYCERA  435 

or  four  claw-like  booklets.  These  maggots  live  in  decomposing  organic 
matter  ;  they  rarely  live  in  water,  and  some  of  them  are  parasitic.  They 
either  become  barrel-shaped  pupae  within  the  last  larval  integument,  or,  after 
casting  it,  are  transformed  into  pupae.  The  larvae  of  numerous  Brachycera 
have  been  observed  in  man,  some  in  ulcers,  or  on  mucous  membranes, 
others  in  the  skin,  or  in  the  intestine,  &c.  In  many  cases  the  report  only 
mentions  the  presence  of  the  larvae  of  flies  ;  in  other  cases  the  species 
has  been  determined  ;  whilst  in  still  other  cases  the  corresponding  adult 
creature  is  unknown.  We  must,  therefore,  confine  ourselves  to  describing 
the  most  common  varieties. 


1.  Phora  rufipes,  Meig. 

The  larvae  of  the  "  hump-backed  fly  "  live  in  rotting  potatoes,  mush- 
"rooms,  radishes,  &c.,  and  when  accidentally  introduced  into  the  intestine 
of  man  can,  like  other  larvae,  live  there  twenty-four  hours,  and  even 
more,  a-nd  may  set  up  serious  gastric  disturbances. 

[The  larvae  of  the  Phoridce  also  live  in  decaying  animal  matter.  Some 
forms  have  been  found  breeding  in  dead  bodies  (Howard). 

P.  rufipes  is  the  same  as  P.  pallipes,  Latr. — F.  V.  T.] 

2.  Piophila  casei  (L.). 

Cheese  flies.  The  larvae  live  in  ripe  cheese,  with  which  they  are  some- 
times introduced  into  human  beings  (Meschede). 

[The  larvae  •  of  the  cheese  flies  (Piophila  casei}  may  pass  through  the 
alimentary  canal  of  human  beings  alive,  and  have  been  occasionally 
referred  to  in  cases  of  internal  myiasis.  It  also  breeds  ijfe  dead  bodies  in 
adipose  tissue.  Howard  records  it  on  human  excrement.  It  is  thus  possible 
that  some  of  the  recorded  cases  of  this  pest  being  passed  alive  may  be 
due  to  eggs  deposited  on  human  faeces. — F.  V.  T.] 

3.  Teichomyza  fusca,  Macq. 

Syn.  :   Scabella  urinana. 

These  larvae  live  in  the  urine  of  privies,  and  are  said  to  have  been 
repeatedly  observed  in  the  faeces  or  vomit  of  persons -(Davaine,  Rogers, 
Pruvot,  &c.). 

4.  Anthomyia  canicularis,  Meig. 

Syn.  :  Scalaris,  Fabr.,  and  manicata,  Meig.  The  larvae  live  in  vege- 
tables, cabbage,  &c.),  and  are  beset  with  feathered  bristles.  They  frequently 
invade  the  intestine  of  persons,  and  produce  alarming  symptoms  until 
vomited  up  or  passed  with  the  faeces  (Dubois,  Wacker,  Kohn,  Lampa, 
Finlayson,  &c.). 

[This  species  is  known  as  Homalomyia  canicularis,  Linn.  It  is  common 
to  Europe  and  North  America,  and  is  an  abundant  house-fly.  It  is  the 
small  house  fly  so  often  seen  on  windows.  Besides  living  on  vegetable 
matter,  they  have  also  been  found  in  the  nests  of  the  humble  bee.  Larvae 
of  this' species  were  sent  to  the  British  Museum,  taken  from  the  faeces  of  a 


436 


THE    ANIMAL    PARASITES    OF    MAN 


woman  suffering  from  cancer.1  They  were  found  at  Shrewsbury.  Hagen- 
reports  the  larvae  of  this  fly  as  occurring  alive  in  the  urethra  of  a  patient. 
— F,  V.  T.] 

5.  Homalomyia  scalaris,  Fabri. 

[This  is  not   a  synonym  of   the   above,   but   a   distinct   species. 
H.  manicata,  Meigen,  is  also  distinct. — F.  V.  T.] 


6.  Musca  domestica,  L. 

and  M.   (Calliphora)  vomitoria,  L.  and  allied  species  ;    the   larvae   have   been 
repeatedly   found  in  the  intestine  and  nose  of  man  (Mankiewicz,   &c.).-! 


FIG.  278. — Larva  of 
A  nthomyia  Ca  nicularis 
(enlarged). 


FIG.  279. — Larvae  of 
Musca  vomitoria  (en- 
larged). 


FIG.  280.  —  Larva  of 
Lucilia  macellaria.  (After 
Conel.)  4/1. 


7.  Lucilia  macellaria  (Fabricius),  1794. 

Syn. :  Luc.  hominovorax,  Coq.,  1858;  Calliphora  infesta,  Phil.,  1861  ;  Calli- 
phora  anthropophaga,  Co  nil,  1878. 

An  American  fly  which  deposits  its  eggs  on  ulcers,  in  the 
auditory  canal  or  in  the  nostrils  of  persons  who  may  be  sleeping 
in  the  open  air.  The  larvae  (screw  worms),  which  are  provided 


1   "First  Report  Economic  Zoology,"  p.  55,  Brit.  Mm.  (Nat.  Hist.),  Theobald. 
-  Hagen,  Proc.  Bost.  Soc.,  N.H.,  xx.,  107. 

3  Larva  of  a  Musca,  probably  M.  corvina,  were  passed  in  numbers  per  rectum 
by  a  child  in  Liverpool  with  Homalomyia  larvae. — "  Second  Report  Economic 
Zoology,"  p.  16,  1963,  Theobald. 


LUCJLIA    NOBILIS 


437 


with  strong  spines,  work  themselves  into  the  nasal  and  frontal 
sinus,  into  the  pharynx,  larynx,  &c.,  perforate  the  mucous  mem- 
branes and  even  the  cartilage,  and  may  cause  the  death  of  their 
host  (Coquerel,  Philippi,  Francius,  Humbert,  &c.). 

[This  species,   the  screw  worm  fly,  is  known  as   Compsomyia  macellaria, 

It    attacks    animals    as    well    as    man,    especially    laying    its    eggs    ori 

wounds    formed    by    barbed    wire.      It    may    also    be    found    on    dead    flesh. 

Dr.    St.    George    Gray    sent    me    specimens    from    St.    Lucia,    from    the    nose 


FIG.  281. — The  Screw  Worm  Fly  (Compsomyia  macellaria). 


and  mouth  of  a  patient  in  Victoria  Hospital.  Others  were  found  in  the 
vagina  of  another  patient.  Out  of  the  four  patients  attacked  two  occu- 
pied the  same  bed,  one  after  the  other,  and  a  third  the  next  bed  to  it. 
The  other  case  was  in  a  more  remote  part  of  the  hospital. — F.  V.  T.] 

8.  Lucilia  nobilis,  Meig. 

The  larvae  were  observed  by  Meinert  in  Copenhagen  in  the  auditory  meatus 
of  a  person  who,  after  taking  a  bath,  fell  asleep  in  the  open  air,  and  on 
waking  felt  singing  in  the  ears,  and  had  a  sensation  as  if  there  were 
water  in  the  auditory  canal.  During  the  next  days  severe  pains  set  in, 
and  there  was  a  discharge  of  blood  and  pus  from  both  ears,  as  well  as 
from  the  nose.  On  washing  out  the  meatus  the  maggots  made  their 
appearance. 


438 


THE   ANIMAL    PARASITES    OF   MAN 


9.    Lucilia  ccesar,  Linn. 

[This  golden-green  fly  usually  lays  its  eggs  on  decomposing 
organic  matter;  now  and  again  it  lays  its  eggs  in  wounds  on 
man.— F.  V.  T.] 

10.  Sarcophaga  carnaria  (L.),  1758. 

The  larva  of  this  common  fly  has  been  repeatedly  observed  in  the 
nasal  cavity,  the  conjunctiva,  the  external  meatus,  on  the  prepuce  and 
anus,  in  the  vagina,  in  ulcers  and  in  the  intestine  of  man  (Guyot,  Grube 
Legrand,  &c.) 


FIG.  282. — The  Green  Bottle  Fly  (Lucilia  casar,  Linn.). 

ii.  Sarcophaga  magnified,  Schiner,  1862. 
Syn.  :  Sar.  wohlfahrti,  Portschinsky,  1875. 

Spread  over  the  whole  of  Europe,  but  is  particularly  frequent  in  Russia. 
The  larvae  live  in  ulcers  and  the  canals  and  cavities  of  man  that  are 
directly  accessible  from  the  exterior.  In  these  situations  they  cause  symp- 
toms similar  to  those  set  up  by  Lucilia  macettaria.  Little  children  are 
especially  attacked  in  the  Protectorate  of  Mohilew  (Wohlfahrt,  Gerstacker, 
Portschinski,  &c.). 

[This  fly  is  viviparous.  The  fly  varies  from  10  to  30  mm.  in  length, 
and  is  of  a  general  ash-grey  colour  ;  the  thorax  with  three  dark  stripes, 
the  abdomen  light  grey  with  three  black  spots  on  each  segment  ;  legs 
black  ;  base  of  wings  yellow.  It  also  attacks  animals  and  birds,  especially 
,._F.  V.  T.] 


CONGO  FLOOR  MAGGOT 


439 


12.  Ochromyia  anthropophaga,  E.  Blanch. 

This  fly  is  frequent  in  the  south  of  Senegal,  especially  in 
Uiyor;  the  larvae  (ver  du  Cayor)  develop  in  the  skin  of  man 
logs,  cats,  jackals,  &c.  A  closely-related  form  occurs  in  the 
south-east  of  Africa.  In  consequence  of  their 
manner  of  life  these  larvae  were  usually  mis- 
taken for  the  larvae  of  Oestridcz  until  R. 
Blanchard  recognised  their  real  nature ;  they 
are  the  larvae  of  Muscida  (Berenger-Ferand, 
Lenoir  and  Railliet,  Blanchard). 


[13.  Auchmeromyia  (Bengalia)  depressa  (The 
Maggot  Fly  of  Natal.1) 

This    fly,     which    belongs    to     the     Sarcophagidze, 
produces  serious    cutaneous    myiasis.     It   occurs   from 

DelaSoa   Bay   to   Natal    and    int°    Rhodesia.       It    is 

man,     South      Africa,     common    in    Natal,    from    the    Tugela    downwards. — 
(After  Blanchard.)  3/1.     (Vide   "Second   Report  on  Economic  Zoology,"  p.  112. 
— F.  V.  T.] 


[14.  Auchmeromyia  luteola,  Fabr.  (The  Congo  Floor  Maggot). 

The  maggots  of  this  muscid  fly  occur  in  numbers  in  the  native 
huts  in  the  Congo  region.  They  get  into  crevices,  &c.,  of  the  mud 
floors  and  under  the  sleeping  mats.  At  night  they  crawl  out  and 
suck  the  blood  of  sleepers  and  then  return  to  their  shelter.  The  fly 
is  thickset  and  about  the  size  and  build  of  a  blue-bottle.  Length 
10 — 12  mm.  Tawny  in  colour  with  small  black  hairs  covering  its 
body,  giving  it  a  smoky  appearance.  The  flattened  thorax  has 
longitudinal  black  and  brown  stripes  ;  the  abdomen  has  a  dark  line 
in  the  centre  of  the  second  segment  which  meets  a  dark  line  in  its 
posterior  border,  the  dark  brown  third  segment  has  a  narrow  yellow 
anterior  line  ;  the  fourth  is  also  dark  with  a  paler  posterior  border. 
The  legs  are  buff,  with  black  hairs  and  bristles.  The  fifth  tarsal 
joint  is  jet  black.  After  a  feast  of  blood  the  maggots  become  red- 
dish.— (Vide  Mem.  xiii.  Liv.  Sch.  Trop.  Med.,  p.  40,  "The  Congo 
Floor  Maggot,"  by  Button,  Todd,  and  Christy.)— F.  V.  T.] 


"  Agri.  Jonrn.  Dept.  Agri.  and  Mines,  Natal,"  vol.  iv.,  p.  606,  1901,  C.  Fuller. 


440 


THE    ANIMAL    PARASITES   OF    MAN 


15.  Hypoderma  bovis  (De  Geer),  1776. 

Ox  hypoderma,  ox  gad  fly,  or  warble  fly.  The  female  deposits  her  eggs 
on  the  skin  of  cattle  ;  the  young  larvae  bore  deep  into  the  subcutaneous 
connective  tissue,  where  they  give  rise  to  characteristic  tumours,  which  may 
attain  the  size  of  pigeons'  eggs.  When  the  larva  has  reached  its  full 
size  it  again  casts  its  skin  and  leaves  its  host  to  become  a  pupa  on  the 
ground.  The  larva  has  also  repeatedly  settled  in  the  skin  of  man  (Spring, 
Joseph,  &C.).1 


16.  Hypoderma  diana,  Brauer,  1858. 

The   larvae    live   in    the    skin   of    deer   and    roedeer  ;    they   have    also,    in 
three  cases,  been  observed  in  man  (Boithen,  Joseph,  Volkel.) 


FIG.  284. — Larva  of  Der- 
matobia  cyaniventris  in  its 
natural  size  and  magnified. 
(After  Blanchard.) 


FIG.  285. — Larva   of   Der- 

matobia       cyaniventris,      en- 
larged.   (After  Blanchard. ) 


17.  Gastrophilus,  sp. 

The  larvae  of  some  species  of  Gastrophilus  live  in  the  stomach  as  well  as  in 
the  duodenum  of  horses.  When  they  have  become  mature  they  leave  the 
intestine  by  the  natural  channel  to  become  puparia  in  the  ground.  Cholod- 
kowsky  states  that  the  "  little  worms "  observed  by  Samson  and  Sokolew 


1  This  species  has  frequently  been  confused  with  H.  lineata,  Villiers  (vide  Second 
Rep.  Sco.  Zool.  1903.)— F.  V.  T. 


DERMATOBIA 


441 


(Wratsch,   1895.  Nos.  48  and  57),   that  bore  fine  canals  in   the  epidermis  of 
human  beings  are  the  young  larvae  of  a  Gastrophilus.1 


1 8.  Dermatobia  cyaniventris  (Macquart),  1840. 

Syn.  :  Cuterebra  noxialis,  Goudot,  1845  ;  Dermatobia  noxialis,  Brauer, 
1860. 

The  Dermatobia  flies  in  tropical  America  take  the  place  of  our  species  of 
Hypoderma,  and  their  larvae  live  in  the  skin  of  mammals,  as  well  as  of 
human  beings.  In  Mexico  they  are  called  "  Moyoquil,"  in  Guiana  "Macaque," 
in  Venezuela  "  Torcel,"  and  in  Brazil  "  Berne."  They  were  formerly, 
at  least  as  regards  their  occurrence  on  man,  considered  to  be  the  larvae 
of  various  species,  till  R.  Blanchard  was  able  to  demonstrate  the  fact 
that  the  different  forms  are  only  consecutive  stages  of  the  same  species 
(Dermatobia  cyaniventris}. 

Sangalli  (1893)  also  identified  this  species  in  Italians  returned 
from  Brazil. 


FIG.  286. — Dermatobia  noxialis,  Goudot. 


19.  Dermatobia  noxialis,  Goudot. 

[Dermatobia  cyaniventris,  Macquart,  1843,  is  not  tne  same  as  noxialis  (vide 
Brauer,  p.  266).  It  is  known  by  various  other  names,  as  Nuche  or  Gusano  in 
New  Grenada  ;  the  Ura  in  Brazil,  and  the  Macaw  fly  in  Cayenne.  It  occurs 
from  Mexico  to  Brazil.  According  to  Goudot  the  fly  is  found  in  great  numbers 
on  the  borders  of  large  woods  and  lands  covered  with  underwood. 

The  cattle  worm,  or  founzaia  ngombe,  is  the  name  given  to  a  larva  which 


1  "  Ueb  einie  seft  biem  Mensch  vork.  Paras."  (Stzgzb.  d.  St.  Petersb.  naturf.  Ges 
1897,  p.  185  ;  Wratsch,  1896,  No.  3  ;  1897,  No.  7  ;  ,'898,  No.  2).  Compare  also  Arch. 
/.  Dermat.  u.  Syph.,  xli.,  p.  367. 


442  THE    ANIMAL    PARASITES    OF    MAN 

develops  beneath  the  skin  of  oxen  and  men  in  Central  Africa,  especially  amongst 
the  natives  and  stock  of  Unyamoriezi.  According  to  P.  Dutrieux,1  the  egg 
is  laid  by  a  large  fly  that  accompanies  cattle.  It  is  unknown  between  the 
central  plateau  or  the  Ugogo  and  the  East  Coast. — F.  V.  T.] 


Biting-mouthed  Brachycera. 
By  F.   V.    Theobald. 

[Amongst  the  division  Brachycera  (as  meant  in  this  work)  we  get  several 
groups  of  flies  which  like  the  fleas  and  mosquitoes  are  partially  parasitic  on 
man,  the  adults,  mainly  in  the  female  sex,  being  provided  with  a  piercing 
mouth  with  which  they  extract  the  blood  of  man  and  animals.  The  importance 
of  these  parasites  is  not  the  mere  fact  that  they  feed  upon  our  blood,  but  that 
they  in  all  probability  often  carry  germs  from  man  to  man  (Tsetse  flies  and 
Trypanosomosis,  Tabanidae  and  Anthrax).  Amongst  the  most  important  biting- 
mouthed  diptera  in  this  section  are  the  following  :  Tabanidce,  or  Gad  Flies, 
Glossince,  or  Tsetse  flies ;  and  certain  other  Muscidce.  Some  of  the  exotic 
Asilidce  and  a  few  Leptidce  also  bite  man. 

Family  Tabanidce  or  Gad  Flies. 

The  Tabanidae  have  a  broad,  rather  flattened  body  and  a  large  head ; 
eyes  united  in  the  male.  The  antennae  have  the  third  joint  composed  of 
five  to  eight  annuli.  The  proboscis  is  projecting,  and  sometimes  much 
elongated.  The  legs  are  moderately  stout.  The  venation  of  the  wings  is 
shown  in  the  figure  287. 

This  family  of  Gad,  or  Horse  flies,  contains  a  great  number  of  genera,  all 
of  which  bite  animals  and  man  more  or  less  severely.  The  female  alone 
is  blood  sucking,  the  males  feed  upon  the  juices  of  flowers.  The  females 
deposit  their  spindle-shaped  eggs  on  leaves,  stems  of  plants  that  either 
overhang  or  stand  in  water,  and  amongst  rushes  ;  they  are  at  first  white, 
but  become  brown  or  black.  The  eggs  are  laid  in  convex  masses  com- 
posed of  layers  one  upon  the  other.  The  larvae  are  carnivorous,  feeding 
upon  snails,  other  larvae,  &c.,  and  have  a  distinct  head  ;  they  are  com- 
posed of  eleven  segments,  the  last  with  a  vertical  breathing  pore,  or  the 
last  two  segments  may  form  a  breathing  tube.  The  majority  taper  to  a 
point  at  each  end,  in  colour  shining  white  or  dull  grey,  many  of  the 
larger  specimens  banded  with  dark  brown  or  black.  The  young  larvae 
burrow  into  any  soft  substance,  animal  or  vegetable  ;  they  live  both  in 
the  water  and  under  damp  soil  surrounding  water,  also  in  damp  earth 
generally.  The  larvae  are  not  only  carnivorous,  but  they  are  cannibals, 
frequently  devouring  their  own  species.  They  may  take  more  than  a 
year  to  mature. 

The  pupae  are  found  close  to  the  surface  of  mud  and  earth,  and  are 
mostly  dull  yellowish  in  colour  with  rows  of  spines  at  the  apical  third  of 


1  "  Apercu  de  la  pathologic  des  Europeans  dans  I'Afrique  intertropicalc,"   ThZse  de 
Paris,  p.  60,  1885. 


TABANID^E 


443 


each   abdominal   segment,   and   there   are   also   denticles   at    the  apex  of   the 
abdomen. 

A   habit   common    to    the   adults   of   most   of   the   Tabanidse   of  consider- 


FIG.  287.— The  Ox  Gad  Fly  (Tabanus  bovinus,  Linn.). 


FIG.  288. — The  Brimp  (H&matopota  pluvialis,  Linn.). 

able  economic  importance  is  that  of  the  adults  coming  to  water  to  drink. 
Porchinski1  has  found  that  by  applying  kerosene  to  the  pool  they  frequent 
that  the  adults  are  killed,  and  Hine2  that  the  same  oil  kills  the  larvae  that 
fall  into  the  water  from  eggs  laid  on  plants  above. 


1  Vide  Bull  20  N.  Sc.  U.  S.  Division,  Ento,  I'.S.A. 

-  Tabanidte  of  Ohio,  Ohio  State  University.     Bull,  19,  Sc.  7,  p.  14,  1903. 


444  THE    ANIMAL   PARASITES   OF    MAN 

There  are  two  main  sections  (i)  Pangonince  in  which  the  hind  tibiae  have 

spurs  at  the  tip,  and  (2)  the  Tabanince  in  which  the  hind  tibiae  have  no  spurs. 
The   chief  annoying  genera  are   told   by   the   following  characters  : — 

Proboscis  very  long  ;    hind  tibiae  with  spurs  at  the  tip  .  .  .  .      Pangonia. 

Proboscis  short ;  wings  with  dusky  markings  ;  ocelli  present  .  .      Chrysops. 

Hind   tibiae  without  spurs  :    thorax  and  abdomen  with  irri- 

descent  tomentum  ;  all  tibiae  dilated  . .  •:       ,.          ..     Hadrus. 

Thorax  and  abdomen  without  tomentum  ;  third  joint  of  anten- 
nae without  well  developed  basal  process  ;  wings  mottled 
and  overlap  .  .  . .  . .  . .  . .  .  .  ...  Hcematopota. 

Eyes  bare  ;  last  joint  of  antennae  notched  in  crescent  form       .  .      Tabanus. 

Eyes  pubescent ;  a  small  ocelligerous  tubercle  present. .  .          . .      Therioplectus. 

No  ocelligerous  tubercle     ..          »>  i      ..          ..          ..       •  » .     Atylotus. 

Great   numbers   of   these   flies   bite   man   in   all  climates.      The   Pangonia 

can    pierce    even    through    thick    clothing.      Chrysops    and    H&matopota    pro- 


FIG.  289. — The  Stinging  Fly  (Stomoxys  calcitrans,  Linn.). 

duce  most  pain  in  man  when  biting.  A  common  Haematopota  is  H.  pluviahs 
or  the  '  Brimp  '  found  in  Europe.  It  bites  men  severely.  H.  crassicornis  is  also 
sometimes  annoying.1 

Family  Asilidcz  or  Wolf  Flies. 

These  flies  are  of  little  importance  in  regard  to  the  subject  dealt  with 
in  this  book  ;  but  I  have  had  notes  sent  concerning  the  biting  habits  of 
one  or  more  species  belonging  to  this  family.. 

Asilidce,  or  Wolf -flies,  are  easily  told  by  the  following  characters  : — 
Large  or  moderate  sized  flies,  thickly  hairy  ;  head  separated  from  thorax 
by  a  narrow  neck  ;  eyes  separated  in  both  sexes ;  proboscis  firm  and  horny, 
adapted  for  piercing  ;  abdomen  long,  pointed,  and  composed  of  eight  seg- 
ments. Legs  strong  and  bristly,  of  moderate  length.  Wings  sometimes 
mottled,  lying  parallel  over  the  abdomen  when  at  rest.  There  are  nearly 
3,000  species.  They  live  mostly  upon  insects,  but  some  are  said  to  bite 
animals  and  man.  They  are,  however,  of  little  importance  in  this  respect. 

1  Second  Report  Economic  Zoology,  p.  15,  1903,  Theobald. 


MUSCID.Si 


445 


Family  Muscidce  (in  widest  sense). 

This  large  group  of  flies  contains  a  host  of  varied  forms  ;  such  insects  as 
the  house  fly  may  be  taken  as  an  example.  Some  have  been  referred  to 
in  this  book  as  being  parasitic  during  larval  life  (Compsomyia  macellaria, 
Sarcophaga  magnified,  &c.)  ;  there  are  others,  however,  not  referred  to  here 
which  must  be  mentioned,  namely,  Stomoxys,  Glossina,  H&matobia,  Hydro- 
phoria,  Hydrotaea,  and  Aricia. 

The  Stomoxys,  or  Stinging  Flies,  have  a  solid  elongated  proboscis,  bent 
near  its  base,  extending  beyond  its  head  ;  its  palpi  are  shorter '  than  the 
proboscis.  They  are  also  known  as  cattle  or  stable  flies.  One  of  the 
chief  species  is  S.  calcitrans — a  fly  which  is  common  to  Europe  and  North 
America  ;  has  a  wide  distribution.  The  larvae  live  in  horse  manure,  the 
adults  upon  the  blood  of  animals.  It  has  a  superficial  resemblance  to  the 


FIG.  290. — The  Tsetse  Fly  (Glossina  morsitans,  Westwood). 

common  house  fly,  but  can  at  once  be  told  by  the  projecting  proboscis. 
They  bite  man  viciously  even  through  thick  clothing.  Various  species 
occur  in  the  Tropics.  It  is  noticed  that'  this  fly  invades  houses  and  stables 
prior  to  a  storm  of  wind  and  rain. 

The  Horse  Fly  (H&matobia  irritans,  L.)  attacks  cattle  chiefly,  but  now  and 
then  man  is  bitten.  The  different  species  can  be  told  from  Stomoxys  by 
"the  palpi  being  nearly  as  long  as  the  proboscis. 

Hydrotaea  meteorica,  L.  (the  Meteoric  Fly).  This  fly  attacks  man  as 
well  as  animals.  They  especially  bite  around  the  eyes  and  nostrils  of 
animals,  but  are  not  so  particular  with  man  ;  the  head,  however,  is  usually 
chosen.  Linnaeus  called  it  the  Meteoric  Fly,  because  it  often  forms  clouds 
around  horses'  heads  at  the  approach  of  rain.  The  Hydrottsas  come  in  the 
family  Anthomyidce,  and  are  usually  black  or  blue-black  in  colour  with 
bare  eyes  and  simple  abdomen,  the  front  femora  peculiarly  constructed 

The  genus  Hydrophoria,  Desvoidy,  also  bites  man. 


446 


THE    ANIMAL    PARASITES    OF    MAN 


Glossina  (Tsetse  Flies). 

Eight  different  species  of  Tsetse  fly  are  known.1  They  all  bite  animals  and 
man.  They  occur  only  in  Africa.  The  so-called  N'gana  of  horses,  &c.,  is 
distributed  by  one  of  these  flies.  The  bite  is  not  very  painful  to  man,  but  their 
importance  lies  in  the  fact  that  they  carry  the  Trypanosome  of  sleeping  sick- 
ness and  other  species. 

The  following  is  Austen's  revised  synopsis  of  the  species  of 
Glossina  2:  — 

"  i.    Hind  tarsi  dark,  or  at  least  all  the  joints  more  or 

less  dark  (in  the    $  of  Glossina  tachinoides,  the 

basal  half  of  the  first  joint  and  the  extreme  base 

of  the  following  joints  are  usually  pale.  .  2. 

"  Hind  tarsi  not  entirely  dark  ;  last  two  joints  alone 

dark,  remainder  pale          .  .  .  .  .  .  4. 

"  2.    Ground  colour  of  abdomen  ochraceous  buff,  with 

interrupted  dark  brown  deep   transverse  bands 

and  sharply  defined   pale  hind  borders   to    the 

segments  ;  a  very  conspicuous  square  or  oblong 

pale  area  in  the  centre  of  the   second  segment  ; 

small  species,   not   exceeding  8   mm.   in   length 

(exclusive  of  proboscis),  the  males  considerably 

smaller 
"  Abdomen   not   so  marked,  very   dark  or   for    the 

most   part   uniformly    brown,    hind    borders    of 

segments  if  lighter  extremely  narrow  and  cine- 

reous ;   pale   area  in  centre   of  second   segment 

usually  triangular  with  the  apex  directed  back- 

wards   and    continued   into  a  cinereous  median 

stripe  ;  larger  species          .  . 
"  3.   Third  joint  of  antennae  dusky  brown  to  cinereous 

black  ............ 

"  Third  joint  of  antennae  pale  (orange  buff)  .  . 
"4.    Large    species  :    length  at  least   n   mm.,  wing  ex- 

panse measured  from  tip  to  tip  when  wings  are 

set  at  right  angles  to  body,  at  least  25  mm. 
"Smaller   species:    length  rarely  reaching   n  mm., 

often   considerably  less  ;    wing   expanse   not  ex- 

ceeding 25  mm. 
"  5.    Last  two  joints  of  front  and  middle  tarsi  without 

sharply  defined  dark  brown  or  black       .  .          .  . 
"  Last  two  joints  of  front  and  middle  tarsi  without 

sharply  defined  dark  brown  or  black  tips,  front 

and   middle    tarsi    entirely   yellow,  or   last    two 

joints  of  former  faintly  tipped  with  pale  brown        Pallidipes,  Austen. 


TachinoideSy  Westw. 


Palpalis,  Rob.  Desv 
Pallicera,  Bigot. 


7- 


5- 


6. 


1  "  Monograph  Tsetse  Flies,"  E.  Austen,  British  Museum,  Nat.  Hist.,  1903. 

2  "Supplementary  Notes  on  the  Tsetse  Flies,"  Mem,  XIII.  Liv.  Sch.  Trop.  Med., 
p.  in,  1904. 


PUPIPARA  447 

"6.    Generally    distinctly    larger  ;    head    wider  ;    front 

darker  and  narrower  in  both  sexes,  sides  parallel 

in    the    $  ;    abdominal   bands    deeper,    leaving 

hind   margins  of  segments  only  narrowly  pale  ; 

hypopygium   in    $    smaller,    darker,    and    more 

hairy  ;  tip  of    $  abdomen  more  thickly  clothed 

laterally  with  short  black  hair,  bristles  on  sixth 

segment  finer  and  less  prominent  . .          . .     Longipalpis,  Wied. 

"  Usually  smaller  ;  head  narrower  ;  front  paler  and 

wider ;  eyes  in  $  as  well  as  in  $  distinctly  con- 
verging towards  vertex  ;   abdominal  bands  less 

deep  ;  pale  hind  margins  of  segments  therefore 

deeper;  hypopygium  in    $    larger,  paler,  some- 
what  more   oval  in   outline,   and   clothed  with 

fewer  fine  hairs ;  tip  of  3   abdomen  less  hairy 

laterally  ;  bristles  on   the   sixth  segments  in   $ 

stouter  and  more  conspicuous       .  .          .  .          . .  Morsitans,  Westwood. 

"  7.    Dorsum    of   thorax    with  4   sharply-defined   small 

dark-brown  oval  spots,  arranged  in  a  parallelo- 
gram,  2   in   front   of  and    2   behind   transverse 

suture  ;  bulb  at  base  of  proboscis  brown  at  the' 

tip  ....     Longipennis,  Corti. 

"  Dorsum    of    thorax   without   such  spots,   though 

with  more  or  less  distinct  longitudinal  stripes  ; 

bulb  at  base  of  the  proboscis  not  brown  at  tip  . .  'Fusca,  Walker." 
The  most  important  species  is  Glossina  palpalis  of  Robineau-Desvoidy, 
as  it  acts  as  the  carrier  of  the  Trypanosomes  of  man  (Trypanosoma  gambiene}. 
Brumpt  considers  that  the  Tsetse  disease  of  domesticated  animals  is  carried 
by  at  least  five  species  of  Tsetse  Flies,  and  his  investigations  lead  him  to 
suppose  that  sleeping  sickness  may  be  carried  by  several  species.  Other 
diptera  also  carry  Trypanosomes,  such  as  Storm  Flies  (Stomo.vys}. 


Pupipara  or  Eproboscidae. 

The  pupipara  are  all  blood-suckers,  the  majority  occurring  as  parasites  on 
mammals  and  birds.  Occasionally  some  may  attack  man.  They  all  produce 
their  young  fully  formed  as  puparia.  The  puparia  are  large  and  when  passed 
out  may  contain  a  nearly  mature  pupa.  One  ,,  puparium  is  passed  at  a 
time.  They  are  mostly  flat,  louse-like  flies  which  may  or  may  not  be  winged. 
The  winged  forms  have  a  short  quick  flight,  and  when  disturbed  will  seek 
shelter  in  man's  hair  or  beard.  Two  main  families  occur  (i)  the  Hippoboscidcs 
and  (2)  the  Nycteribida.  The  former  occur  on  animals  and  birds,  the  latter 
on  birds  only,  but  may  invade  man.  Two  other  families  are  known — the 
Braulidce  (bee  parasites)  and  the  Strebbidce  (bat  parasites). 

The  mouth  of  the  Hippoboscidce  is  long  and  sharp,  forming  a  proboscis. 
Thorax  and  abdomen  are  flat  and  leathery.  The  legs  are  stout  and  strong 
and  terminate  in  large  dentate  claws  and  other  structures  of  use  in  holding 
on  to  the  hair  or  feathers  of  their  host  when  blood-sucking. 


448  THE   ANIMAL   PARASITES   OF   MAN 

Two  wings  are  present  in  the  true  Hippoboscas,  Hippobosca  equina  (of  the 
horse),  H.  camelina  (of  the  camel),  H.  maculata  (of  oxen),  and  H.  canis  (of 
dogs),  or  absent  in  Melophagus,  the  Sheep  Tick  or  Ked  Fly  (M.  ovinus). 

In  one  genus,  Lipotena,  wings  are  at  first  present,  but  are  lost  as  soon  as 
the  fly  finds  its  permanent  host. 

As  recently  suggested,  these  parasites  may  have  some  connection  with  the 
spread  of  Trypanosomiasis  (vide  Journal  of  Pathology,  1904,  Theiler). — F.  V.  T.] 

The  following  is  the  most  important  literature  on  Diptera  in  general : — Meigen, 
J.  W.,  Syst.  Besch.  d.  bek.  eurc.p.  zweiflugligen  insecten.,  7  vols.,  Hamm.,  1818-1838; 
Brauer,  F.,  Monographie  dev  (Estriden,  Wien.,  1863  ;  "  Idem,  Nachtr.  hierr.u  "  (Wien. 
entom.  Ztg.,  1887,  vi.,  pp.  4,  71);  Schiner,  J.  R.,  Fauna  austriaca,  die  Fliegen., 
Wien.,  1860-64;  Low,  Fr.,  "  Ueber  Myiasis  und  ihre  Erzeuzer"  (Wien.  med.  Wchnsr.hr., 
1882,  xxii.,  p.  247;  1883,  xxxiii.,  p.  972;  Joseph,  G.,  "  Ueb.  Fliegen  als  Schddlinge 
und  Parasiten  des  Menschen"  (Dtsch.  med.  Ztg.,  1885,  i.,  p.  37;  1887,  iii.,  pp.  713 
and  725);  Peiper,  E.,  Fliegenlarven  als  gelegentl.  Paras,  d.  Mensch.,  Berlin,  1900; 
Theobald,  F.  V..  "Monograph of  the  Culicidaeof  the  World,"  3  vols,  and  i  atlas,  plates, 
1901-1903;  Austen,  E.,  "A  Monograph  of  Glossina  Tsetse  Flies,"  i  vol.,  1903.  The 
full  special  literature  will  be  found  in  Peiper  as  well  as  in  Huber's  Bibliographic  d. 
klin.  Entomol.,  1899,  vol.  3,  Jena. 


INDEX. 


Acanthiada 

PAGE 

397 

Acanthocephala     ... 

341 

,,               Species  of,  in  man 

344 

,,               Structure  and   develop- 

ment of 

341 

Acarina     ... 

350 

Acartomyia,  Theob  

431 

Akamushi... 

354 

Aldrichia,  Theob. 

427 

Alveolary  colloids 

257 

Amblyomma  cayennense  ... 

367 

Amceba  buccalis    ... 

37 

,,       coli 

30 

,,      dentalis    ... 

37 

,,       Ehrbg  

29 

>  >      gingivalis 

37 

,  ,      kartulisi  ... 

38 

,,      miurai     ... 

39 

,,     pulmonalis 

37 

,,       urogenitalis 

37 

Amabina  .... 

25 

Angiostomidce 

277 

Anguillulidce 

275 

Anguilhdina 

276 

,  ,           putrefaciens 

276 

Animal  parasites  of  man 

25 

Ankylostoma,  Dubini 

327 

,  ,           duodenale  ... 

327 

Anopheles,  Meigen 

425 

Anophelina 

425 

Aphaniptera 

403 

Arachnoidea 

350 

Argas  chine  he 

372 

,,     persicits 

37i 

,,      reflexus 

36i 

Arthropoda 

349 

Arribalzagia,  Theob. 

426 

Aacaris  cants 

336 

,.      L. 

333 

,  ,      lumbricoides 

333 

,  ,      tnarilima 

338 

Asiliittf      •  •  • 

444 

29 

Auchmeromyia  dcpressa  . . . 
, ,  Inteola     . . . 

Balantidium 

»          colt  ... 

,,  ininutum     ... 

Beri-beri,  Hrematozoa  in 
Biting-mouthed  brachycera 
Bothriocephaloidea  , 
Bothriocephalus  niansoni 
Brachycera  (flies)... 


434 


Case-worm,  Structure  and  development  of 

Cellia,  Theob 

Ceratopogon 

Cercomonades  in  the  urine 
Cercomonas  hoininis 

Cestodes,  Rud 

,,        Abnormalities   and    malforma- 
tions of 

,,        Anatomy  of  the 
,,        Biology  of  the  ... 
,,        Characteristics  of  the  ... 
,,        Classification  of  the     ... 
,,         Development  of  the    ... 
,,        of  man  ... 
Change  of  host  in  parasites 
Cheyletus  mericourti 
Chigoe 

,,      of  fowls     ... 
Chironotnidcs 
Ciniex  ciliattis 
,,      lectulartus 
,,     rotitndatus 

Classification  of  the  Cestodes     ... 
, ,  , ,       Coccidiida  ... 

, ,  , ,       CulicidiT     ... 

, ,  , ,       Glossina 

,,  ,,       Hexapoda  ... 

,,  ,,       Ixodidce 

, ,  , ,       Nematodes ... 

,,  ,,       Platyhclminthes    ... 


I'AGE 

439 
439 

120 

121 
125 
102 
442 
213 
222 
,  442 

252 
427 

433 
54 
5i 

1 86 

211 
190 
209 

186 

212 
200 

213 
21 

379 
405 
406 

433 
398 
397 
398 

212 

77 
421 
446 
393 
362 
274 
128 


450 


THE    ANIMAL    PARASITES    OF    MAN 


Classification  of  the  Protozoa 

PAGE 

27 

Dicroccclium  lanceatum  ... 

I'  AGE 
...         174 

,,               ,,        Trematodes 

147 

Diplogonoporus  grandis  ... 

...       221 

Coccidia  of  dura  mater    ... 

84 

,,              Lonnbrg. 

...       221 

,,         excretory  organs 

84 

Diptera     

...       403 

Coccidiida... 

68 

Dipylidium  caninum 

...       223 

,,         Classification  of  the.. 

77 

„           R.  Leuck.    

...       223 

,,         Development  of  the 

74 

Distomuni  rathouisi 

...       159 

,,         History  of  the 

68 

Doubtful  species  of  Coccidia 

...          82 

,,         Occurrence  of  the    .. 

72 

,,               ,,          Plasmodium 

.-        95 

,,         The,  observed  in  man 

77 

Coccidio  ides  i  m  in  it  is 

83 

Echinococctts  multilocularis 

...     257 

Coccidium  bigeminum 

81 

,,         Structure  of 

...     252 

,,         cuniculi 

77 

Echinorhynchus  gigas 

...     344 

,,         Doubtful  species  of  ... 

82 

,,                hominis... 

...     344 

,,         hominis 

80 

,,                inonilifonnis 

•••     345 

Coleoptera  .. 

403 

7?  '           'It         '     ' 

82 

Conoi'hnnts  nigrovarius  .  .  . 

Hu»j 
400 

Entozoa     ... 

O-£ 

2 

,,          protractus     ... 

400 

Epizoa 

2 

renggeri       

400 

Eproboscidff. 

...     447 

,,           rubrofasdatus 

399 

Eupodidce  ... 

••     357 

-^     ,,           sanguisuga  ... 

398 

Eustrong-ytus,  Dies. 

...     322 

\  ,,          sp.  novum    ... 

399 

gig™ 

...     322 

\  ,          variegatits    ... 

400 

Coriscus  subcoleoptratus  ... 

401 

Fasciola  hepatic  a  ... 

150,  156 

Cotylogonimus  heterophyes 

172 

„       L  

•     M9 

Cutex,  Linnaeus  ... 

429 

Fasciolidtz,  Raill  .  .  .  . 

...     149 

Culicidse  or  mosquitoes  ... 

415 

Fasciolopsis  buski 

...     159 

Culicina    ... 

427 

,,          Looss 

...     158 

Cycloleppteron,  Theob.    ... 

•425 

Filar  ia  bancrofti  ... 

...     288 

Cysticercu  s  acanth  otrias  ... 

240 

,,      conjunctive 

•••     303 

,  ,      deniarquayi 

..     296 

Davainea  asiatica 

233 

,  ,      diurna 

...     292 

,,         madagascariensis 

232 

,,      equina 

•••     305 

R.  Blanch  

231 

,,      hominis  oris 

••      305 

De  niodex  folliculoru  m 

386 

,,       immitis    ... 

...     285 

Demodicidce 

.3^5 

,  ,      kilmarce   ... 

..      309 

Derivation  of  parasites    .  .. 

20 

,,       labialis     ... 

••      305 

Dermacentor  reticulatus  ... 

368 

,,      ha 

•  •     3°o 

Dermanyssus  gallince 

358 

,,       magalhaesi 

...     299 

,,            hirundinis 

358 

,,       medinensis 

...     282 

Dermatobia  cyaniventris 

441 

,,      occuli  humani 

...     302 

,,           noxialis 

441 

,  ,       ozzardi 

...     297 

Development  of  the  Acanthocephala     ... 

34i 

,,      Persians   ... 

293 

,,               ,,      Coccidiida  ... 

72 

,,       romanortim-orientalis    .. 

•-      307 

,,               ,,      Insecta 

39^ 

,,      sp. 

...     309 

,,               ,,      Myxosporidia 

106 

,,      volvulus  ... 

...     307 

,  ,               ,  ,      Nematodes.  .. 

271 

Flagellata  (Mastigophora) 

...       41 

,,               ,,      Sarcosporidia 

"3 

Flat-  worms 

...     127 

,,               ,,      tape-  worms 

203 

Fleas          

403 

,,               ,,       Trematoda... 

139 

Flies  (Brachycera) 

•      434 

,,               ,,       Trichinella  spiralis 

3M 

Dibothriocephalus 

213 

Gad-flies    

...     442 

,  ,               cordatus 

220 

Gamasidce  ... 

...     358 

,,                latus  ... 

2I4 

Gastrodiscus  hominis 

149 

Dicrocculiuni,  Dai^. 

173 

Gastrophilus,  sp.  ... 

...     440 

INDEX 


451 


General  characteristics  of  the  Protozoa... 

PAGE 
25 

Jigger 

PAUE 
408 

Glossina     ... 
Glyciphagus  buski 

446 

377 

Jointed  -limbed  animals  

349 

,,         prunorum    ... 

377 

Kedani 

1C  A 

Gnathosloma,  Owen 

281 

Jj'r 

Gnatkostowida     ... 

281 

Gordiacea  ... 

34.O 

Lamblia,  Blanch.             

...          48 

Grabhamia,  Theob  

jtu 
430 

,,        intestinalis 

...          48 

/"*                                      '    7 

Leeches     ... 

-J4.IT 

Gregannida 
Guinea-  worm 

63 
282 

,,        with  jaws 

Jtj 

.."347 

,*,        with  rostrum      

-     348 

Hcemadipsa 

^48 

Leptus  au  tu  mnalis 

•••     35i 

H(zmani(cba  in  leucaemia 

sv 

103 

Leucaemia,  Hnemamoeba  in 

...     103 

ff  if  maphy  salts  punctata  ... 

368 

Leydenia   ... 

...       40 

Hamatozoa  in  beri-beri  ... 

102 

Lice 

...     394 

Hamentaria          ...          ...          ...     ,     ... 

348 

Limnalis  ... 

...     348 

H&mosporidia 

84 

,,         nilotica 

...     348 

,,           History  of  , 

84 

Litiguatula  rhinaria 

...     387 

,,           in  birds,  reptiles,  amphibia, 

Linguatiilida 

...     387 

fishes 

103 

Liver  fluke 

...     150 

,,           of  man 

90 

Lucilia  c&sar 

438 

Helminthes 

2 

,  ,       macellaria 

436 

Hermaphroditism 
Hcxapoda  ... 

4 

390 

,,       nobilis 
Lyctocoris  campestris 

437 
402 

Hirudinea,  sp.  Discophora 

345 

Lygaidcz    ... 

.  .  .     402 

Hirudo,  L. 

347 

,,       medicinalis 

347 

Malaria  plasmodia,  Sporogony  of 

...      95 

,  ,        troctina  ... 

347 

,,       Prophylaxis  of    ... 

...       101 

Histiogaster  spennaticus... 

378 

Man,  animal  parasites  of 

...      25 

Holothyrus  coccinella 

359 

Mansonia,  Blanch. 

...     430 

Hoinalomyia  scalaris 

436 

Mastigophora  (Flagellata) 

...      4i 

Hyalomma  (Zgyptitim 

367 

Megarhinina 

427 

Hymenolepis  diminuta    ... 

229 

Megarhinus 

427 

,,           lanceolata   ... 

230 

Melanoconion,  Theob. 

430 

,,           nana           ...         ... 

226 

Melanolestes  abdominalis 

.  .     402 

Weinland    

225 

,,           inorio 

...     401 

Hypoderma  bovis  ... 

440 

Messmates 

6 

,,         diana 

440 

Me  tore  his  truncatus 

...     166 

Microsporidia 

no 

Incidental  and  pseudo-parasites 

6 

Mites         

••     350 

Influence  of  parasites  on  the  host 

8 

,,     of  the  hair  follicles 

...     385 

Infusoria  ... 

118 

Monas  pyophila    ... 

...      54 

,,         General  observations  on 

118 

Monocystidc  gregarines   ... 

...      84 

Insecta 

390 

Mosquitoes 

407 

„      Structure,      development       and 

Acartomyia,  Theobald 

43i 

classification  of... 

39i 

Aldrichia,  Theobald 

427 

Itch  mites... 

379 

Anopheles,  Meigen  ... 

425 

Ixodes  hexagonus  

366 

Anophelina  (sub-family)      ... 

425 

,,       reduvins   ... 

364 

Arribalzagia^  Theobald 

426 

Ixodidce 

36o 

Cellia,  Theobald      ... 

427 

,,       Classification  of  ... 

362 

Classification  of  Cttlicida  .  . 

421 

Genera  of 

36o 

Culex,  Linnaeus 

429 

,,       Synopsis  of 

363 

Culicidtc 

4i5 

Culicina  (sub-family) 

427 

Tanthinosoma,  Arribalzaga         

428 

Cydoleppteron,  Theobald    ... 

425 

452 


THE   ANIMAL   PARASITES   OF   MAN 


Mosquitoes — continued. 

Grabhamia,  Theobald 

Janthinosoma,  Arribalzaga 

Mansonia>  Blanch.  ... 

Megarhinina  (sub-family)  ... 

Megarhinus  (Robineau-Desvoidy). . . 

Melanoconton,  Theobald     ... 

Mucidus,  Theobald... 

Myzoniia,  Blanch.    ... 

Myzorhynchus,  Blanch. 

Nyssorhynchus,  Blanch. 

Psorophora    .." 

PyretophoruS)  Blanch. 

Stegomyia  scutellaris 

Stegomyia,  Theobald 

Stethomyia,  Theobald         

7  ctniorhynchus 

Theobaldinella  annulata 

Theobaldinella,  Blanch. 

ToxorhynchiiiS)  Theobald  ... 
Mosquitoes  or  Culicidse  ... 

,,         Systematic  remarks  on 

Mucidus,  Theob 

Musca  domestica  ... 
Muscida    ... 
Mutualists... 
Myriapoda 
Myxosporidia 

,,  History  of 

,,  Structure     and     Develop- 

ment of  ... 
Myzomia,  Blanch. 
Myzorhynchus ,  Blanch.  ... 

Nematocera 

Nematodes  (Thread- worms) 
,,          Anatomy  of  the 
,,          Classification  of  the... 
.,          Development  of  the 
,,          observed  in  man       ... 

Nephrophages  sanguinarius 

Notes  on  different  genera  of  mosquitoes 

Nyctotherus faba  ... 

,,  Leidy 

Nyssorhynchns,  Blanch. ... 

Occasional  and  permanent  parasitism  ,.-.- 
Ochromyia  anthroj. 
Opisthorchis  noverca 

,,  sinensis ' 

Origin  of  parasites 
Ornithodorus  mtgnini 

,,  savignyi 

, ,  taleji 

, ,  tholozani 


PAGE 

Ornithodorus  turicata 

430 

Owl  midge 

428 

Oxyuris  rudolphi 

430 

,,        vermicularis 

427 

427 

Paragonitnus,  Braun 

429 

,,            wester  mani 

426 

Paramphistotnidce 

425 

Parasites    ...         ...          ... 

426 

,,         Derivation  of  ... 

426 

,,         Incidental  and  pseudo- 

428 

,,         Influence  of,  on  the  host 

426 

,,         in  general 

428 

,,         Origin  of 

428 

Pediculoides  ventricosus  ... 

426 

Permanent  and  occasional  parasitism 

43° 

Phora  rufipes 

429 

Physaloplera  caucasica     ,  .  .          ... 

428 

,,           Rud.           

427 

Piophila  casei        ...          ... 

415 

Placobdella            ...    •      

407 

Plasniodium,  Doubtful  species  of 

426 

,,            Jttalarice 

436 

SP  

445 

,,            vivax 

6 

Plafyhelminthes    ... 

390 

Polymastigina 

1  06 

Porocephalus  constrictus  ... 

106 

Prophylaxis  of  malaria     ... 

Protomonadina     ... 

1  08 

Protozoa     ... 

425 

,,        Classification 

426 

,,        General  characteristics  of 

Pseudo-parasites  ... 

431 

Psorophora             ...          ...          ... 

261 

Psorosperm  cysts  ... 

262 

Psychodidce 

274 

Pulex  fasciatus     ... 

271 

,,      irritans 

275 

,,     pallipes 

384 

,,     penetrans   ... 

425 

Pupipara  ... 

126 

Pyretophorus,  Blanch. 

126 

426 

Rasahus  biguttatus 

Reduviida 

i 

Reduvius  personatus 

439 

Rhabditis,  Dujardin 

170 

,,         niellyi  ... 

1  68 

.  jj. 

9  y        peiifio    ...         .  .           ... 

10 

Rh  ipiceph  alus  sa  ngu  incus 

374 

Rhizog  lyphus  parasilicus 

372 

Rhizopoda  ...         ...         

373 

Rhodinus  prolixus 

373 

Rhynchobdellidce  ... 

373 
434 
338 
338 

160 

160 

1 49 

6 

20 

6 

8 

i 

10 

356 

i 

435 

333 

332 

435 

348 

95 

92 

94 

93 

127 

43 

390 

101 

51 

25 

27 

25 

6 

428 
84 
434 
407 
403 
407 
405 
447 
426 

401 
398 
400 
275 
276 
275 
369 
378 
29 
402 
348 


INDEX 


453 


Rhynchota  aptera  s.  parasitica 

, ,          hemiptera 
Rhyncota  ... 
Running  mites 


Sand -flies  or  Simulidae    ...          ..     /  ... 
Sarcophaga  carnaria       ...          ... 

,,  magnifica 

Sarcopsylla  gallinacea 

,,          penetrans 
Sar copies  minor   ... 

,,         scabiei... 
Sarcoptidie 
Sarcosporidia 

,,  History  of  the 

,,          Structure    and    develop- 
ment of  the 

,,          The,  observed  in  man     ... 
Schistosomida 
Schistosonmin  hceniatobimn 

,,  japonicuni 

Severi's  monocystide  gregarines 
Silvanus  surinamensis    ... 
Simulida  ... 

Simulium  maculatum     ... 
Spiders,  mites 

Sporogony  of  malaria  plasmodia 
Sporozoa    ... 
Stegoniyia  scutellaris 
Slegomyia,)  Theob. 
Stethomyia,  Theob. 
StrongylidceT        !T7" 

Strongy hides,  Grass! rr-. T.T~— >^ 

Strongylus  apri    ... 

„          O.  F.  Miiller  

,,          subtilis 

Systematic,    anatomical,    and  biological 
remarks  on  mosquitoes 

Tabanida  ... 

Jama        

,,     africana    ... 

,,     confusa 

,,     crassicollis 

, ,     echinococcus 

,,     hominis     ... 

, ,     marginal  a 

,,     saginata    ... 


PAGE 

394 
397 
394 


438 
438 
406 
405 
383 
380 
379 

I  12 
112 


I76 

I76« 
181 
84 
403 
43i 
432 
350 
95 
63 
428 
428 
426 
322 
W, 
324 
324 
326 

407 

442 
233 
246 
248 

243 
249 
261 
242 
243 


Jcenia  scrtata 
, ,  soliuni 
Taniidce  ... 
Tctniorhynchus 

Tape-worms 

,,  Biology  of  the 

,,  Development  of  the 

Ta>  soneinidce 
Tetranychidtz 
Tetranychus  molestissimus 

,,  telarius 

Thread-worms 

j   Ticks          

!  Theobaldinella  annulata  ... 
\  Theobaldinella,  Blanch.  ... 
j  Toxorhynchitis,  Theob.  ... 
!  Transmigrations  ... 

j    Trematoda,  Rud 

Trematodes,  Biology  of    .. 

,,  Classification  of     ... 

,,  Development  of  the 

,,  observed  in  man     ... 

,,  Structure  and  development 

of 

Trichinella,  Railliet 
,,  spiralis 

,,  ,,       Development  of     ... 

Trichocephalus,  Goeze     ... 
,,  trickiuris 

Trichomonas,  Donne 

,,  intestinalis . . . 

,,  pulmonalis 

,,  vaginalis    ... 

Trichotrachelida  ... 
Trombidiidie 

Trombidium  llalsahuate ... 
Trypanosoma 

,,  Gruby 

Tsetse-flies  

Tydeus  molestus    ... 
Typhlopsylla  musculi 
Tyroglyphida 

, ,  farin<c 

,,  longior 

, ,  siro 

Uncinaria  americana 
Wolf-flies  .. 


PAGK 
242 

234 
223 
430 

1 86 

209 

200. 

356 

355 

355 

355 

261 

360 

429 

428 

427 

6 

129 


139 
149 

129 

3" 

3ii 

3H 

309 

309 

43 

44 

47 

43 

309 

35' 

353 

57 

56 

446 

357 
407 

374 
375 
375 
375 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


2  8  1977 

LD  21-100m-7,'52(A2528sl6)476 


I* 


